Cheaper tows?

[Tony[_5_]]

http://www.wired.com/autopia/2013/07/cng-airplane/

could be perfect for a club towplane since we fuel up at the club field 99.9% of the time.

[Bill D]

On Thursday, August 1, 2013 12:30:08 PM UTC-6, Tony wrote:
> http://www.wired.com/autopia/2013/07/cng-airplane/
>
>
>
> could be perfect for a club towplane since we fuel up at the club field 99.9% of the time.

To me it looks like panic and desperation in the face of the impending demise of 100LL.

[Tony[_5_]]

On Thursday, August 1, 2013 4:05:07 PM UTC-5, Bill D wrote:
> On Thursday, August 1, 2013 12:30:08 PM UTC-6, Tony wrote:
>
> > http://www.wired.com/autopia/2013/07/cng-airplane/
>
> >
>
> >
>
> >
>
> > could be perfect for a club towplane since we fuel up at the club field 99.9% of the time.
>
>
>
> To me it looks like panic and desperation in the face of the impending demise of 100LL.

maybe clubs could convert their winch engines to natural gas too that way they only have to deal with one kind of fuel for all glider launching.

[bumper[_4_]]

I don't think it's desperation over the demise of 100 LL, most Huskys, 180 hp Huskys will run just fine on mogas premium (without the crap alcohol).

That said, this example is the 200 hp Husky so needs the higher octane fuel..

I have no idea what Stu was thinking on this, but compressed natural gas (CNG) is basically a non-starter for most of what Huskys are purchased for. The CNG system adds over 135 lb and only gives the gasoline equivalent of 9 gallons of fuel. but that 135 lbs, plus whatever the gas weighs, comes right off the useful load. The extra weight will also serve to detract from the dogs short field and bush flying prowess.

And finally, the CNG tank slung under the belly is composite. Given that composite tanks don't handle impacts well, I cannot imagine having a worse thing along for the ride in an off-field forced landing or accident. 3,600 psi of CNG in a composite tank? If it goes, so will anything nearby . . . no need for an ignition source.

IMO, a really dumb idea . . . at least in this example.

bumper
Husky A1-B

[John Clear]

In article >,
bumper > wrote:
>
>And finally, the CNG tank slung under the belly is composite. Given that
>composite tanks don't handle impacts well, I cannot imagine having a
>worse thing along for the ride in an off-field forced landing or
>accident. 3,600 psi of CNG in a composite tank? If it goes, so will
>anything nearby . . . no need for an ignition source.
>
>IMO, a really dumb idea . . . at least in this example.

It really sounds like this example is just a proof of concept.
Simplest way to add the CNG tank is on the CG, and under the belly
is the only available spot. If the testing doesn't work, just
change the plumbing back to the wing tanks and remove the belly
tank.

Interesting idea, but I think even with a fully engineered solution
the weight of the tanks will be an issue.

John
--
John Clear - http://www.clear-prop.org/

[[email protected]]

I can't say I like the idea of sitting on a compressed gas tank one bit.

I think the following is a much more appropriate option:

http://members.glidingclub.org.au/airflow/live/2009_05/eTug%20Trial

Brgds,

Casey

[[email protected]]

Follow up information, reproduced from GCV's Speing 2011 "Airflow" newsletter.

THE SEARCH FOR THE IDEAL GLIDER TUG

(The development and testing of the eTug) __________________________________________________ ____________________

Introduction

In 2005 a syndicate was formed to see if something practical could be done to create an automotive-engined aircraft that would reduce the rising costs of aerotowing and be able to be certified by CASA and replicated for a number of clubs.

Knowing of the history of Autotug in Queensland, we approached Dave Sharples and asked him to join and oversee the project with us.

We named the project eTug (short for “enviro-Tug�) because we intended that it should have a “friendlier� footprint than current tugs – apart from being a lot cheaper to operate, it must be quieter, more efficient in terms of tows-per-engine-hour, more fuel-efficient, cause less impact and erosion damage to grass strips and deposit no lead into the atmosphere.

We have had questions from many people about the project, so this document aims to summarise how we arrived at the specifications for eTug, to answer questions about the other possibilities we examined and to report on the progress and cost benefits of the prototype.

The aircraft we examined which are described here are all well-known, certified and competent as GA aircraft. However, our interest was to evaluate them against the special set of requirements that we developed for our “ideal glider tug�.

As well as applying our own experience, we have talked to a lot of people in the gliding movement with experience in pretty well every method of aerotowing.

The conclusions we reached as a result are set out here, in the progress of the development of eTug.

Specifications and Performance

Towing a glider into the air behind a tug aircraft appears to be a relatively simple process to define and specify. In reality, it is. In the discussion of the theory, however, it attracts all sorts of methods that often reflect the personal interests of the theorists rather than the dispassionate evaluation of the available possibilities. And it should be noted that the original automotive-engined glider tug, Autotug, after flying for 17 years with a Ford Javelin V6 engine, has now been modified to run a GM LS1 5.7 litre V8 engine.

As a syndicate interested in finding the most effective way of reducing aerotow costs, we set out to specify the requirements as objectively as possible, as well as to apply advances in engine technology that have emerged since.

We looked at Eastern Australia, and the rather particular needs we have for aerotowing, and at Lake Keepit specifically as a good example of the requirements of the gliding movement. Here they are:

We need an aircraft which is: ï‚· Proven to be robust and simple to fly ï‚· Powerful enough to tow at high climb rates and suitable speeds for glider pilots ï‚· Has sufficient power to easily tow heavy two-seat and heavily-ballasted Open Class gliders ï‚· Capable of rapid turnaround for highest possible number of tows per hour (more than ten) both to satisfy demand as well as to reduce the costs of towing ï‚· Robust and powerful enough to paddock-retrieve at the height of summer, without any doubt of its capacity to do this ï‚· Fuel-efficient

ï‚· Quiet ï‚· Simply maintained ï‚· Cheaply maintained ï‚· Affordable for a gliding club to buy

So, knowing what we needed, here is what we looked at:

ï‚· Jabiru

A syndicate was formed in Lismore a couple of years back to evaluate the suitability of this type for aerotowing. This project had significant factory backing, with the factory delivering a specifically-modified 6-cylinder 115hp Jabiru.

The evaluation revealed that the aircraft was difficult to control on tow at anything less than 70 kts, making things more difficult for the glider pilot. At this speed, its rate of climb was too low for it to operate as a useful glider tug in terms of time-to-release, producing an unacceptably low rate of tows per hour. Fuel consumption appeared to be encouragingly low, but when considered against a greatly reduced tows-per-hour rate, the advantage was nullified. Further disadvantages were doubts about its ability to paddock retrieve, and its light weight and construction.

The factory acknowledged that for safety, the tricycle undercarriage would need to be converted to tail-dragger configuration because of concerns about possible failure of the nose wheel assembly particularly in operations from rough grass strips.

Other modifications suggested and subsequently produced by the factory included increasing the length of the wings and the surface area of the ailerons, and strengthening the tail assembly to better withstand towing stresses. Whether these modifications will render the aircraft suitable to tow to our specifications remains to be seen. Subsequent test flights conducted at Kingaroy indicated that climb rates were inadequate, and in any case, the cost of the modifications appear to increase the total price of the package to well above $120,000. We understand the modification has not remained in production.

 Tecnam – P 92 Echo Super and P 96 Golf

Initially, this looked quite hopeful in that the factory was offering purpose-built aerotow adaptations. Two models were evaluated in NZ, and as far as smooth-strip towing was concerned appeared to perform adequately. However, with no capacity to paddock retrieve (on cold days, let alone hot) and a price tag exceeding A$140,000 for what is a lightweight and arguably not notably robust airframe, we eliminated it from our contenders list. (Interestingly, the two Tecnams which started towing in NZ appear now to be operating on a very limited basis, and our contact with a number of NZ clubs suggests that no new orders have or are likely to be placed.)

ï‚· Cessna 150

Two Queensland clubs have converted Cessna 150s to Cessna 150/180 tugs. Their experience as recounted to us is that the airframe, particularly the tail assembly, will not stand up over time to glider towing stresses. The Kingaroy club Cessna has had the tail section rivets replaced twice in less than 2000 hours. No further rivet replacement is possible, so the empennage has been bolted, apparently. It is said that the next repair will require complete replacement of the empennage. Its tricycle undercarriage will not allow rough paddock retrieves. While inexpensive to buy, the model is now 45 years old and becoming scarce, and in any case, the shortcomings outlined here took it out of contention for us. Kingaroy has replaced its Autotug with LS1 engined Pawnee.

Cessna 150 – Subaru engine

Boona club investigated this combination and found the engine was so heavy the aircraft could never meet W & B limits. The project was recently abandoned.

ï‚· Super Cub - 180

The performance of this aircraft is similar to that of the Aviat Husky (see below) – relatively low rates of climb and low numbers of tows per hour. In addition, it is also becoming a collectors' item, and is consistently increasing in cost, putting it out of consideration.

ï‚· Husky

Looked at in the light of our specifications list, the Husky's shortcomings are: ï‚· Lack of robustness. LKSC had a number of structural failures with their Husky, the last resulting in the aircraft being written off ï‚· Tows at low climb rate ï‚· Descent rate also low ï‚· Hard to achieve high tows-per-hour ï‚· Operates at the limits of its capabilities in hot-weather paddock retrieves ï‚· Expensive to maintain ï‚· No locally available parts

On the positive side, it is relatively quiet and fuel-efficient (although the low number of tows per hour reduces this latter benefit somewhat).

Changing the engine to an automotive type was considered, but rejected as impractical because of the shortcomings listed.

ï‚· Pawnee

This aircraft meets the requirements of the specifications list if the Lycoming engine is replaced with a high-powered automotive engine. In all other respects it fulfils the requirements.

The Pawnee is an ag-strip cropduster. It was designed to carry up to a tonne of fertiliser into the air off rough farm strips. It is enormously strong.. It is a very easy aircraft to fly. There are currently over 70 of them on the register in Australia with an unknown number in sheds and hangars as a spare parts source. The type is still in production via the holder of the Type Certificate in Buenos Aires, Argentina.

One major advantage is that Pawnees are cheap. This is because they are being supplanted in agriculture by larger, turbine-driven aircraft and so have ceased to be generally viable as cropdusters. Our experience suggests that they are all for sale, and at reasonable prices.

The Pawnee is also, however, the tug of choice of many of the gliding clubs in Australia, New Zealand and UK. (In NZ and UK, despite exposure to “lighties� as tugs, some clubs we have contacted are reverting to Pawnees).

The Pawnee's capability to achieve high numbers of tows per hour is noteworthy. On one occasion at Lake Keepit, a Pawnee flown by Ian McPhee performed 84 aerotow launches in a single day. However, the Lycoming engine requires time spent gradually cooling after glider release that limits it to about 7.5 launches to 2,000' in one engine hour.

Its paddock-retrieve capability is outstanding, because it was designed with rough, short landing areas in mind and it was built to withstand the stresses that these operations generate.

In its existing form, though, the Pawnee does have shortcomings. All of them are engine-related.

The Lycoming aircraft engine is expensive to buy, fuel, maintain, repair and fly. It's also noisy (European clubs don't use this sort of engine in tugs because of increasingly onerous noise legislation).

In glider towing, the Lycoming has to operate close to its performance limits, constantly. The result is that almost no Lycoming engine reaches its 2000-hour overhaul level without first needing new cylinders or a top overhaul. Shock cooling on descent is a permanent problem that increases turnaround time and, if not handled well by the pilot, results in cylinder and cylinder head cracking. All of these problems and processes are costly. A top overhaul can run to $18,000. The 2000-hour overhaul costs between $55,000 and $65,000. Spare parts are expensive, as is avgas. And the result of all of these expenses is that an aerotow launch is more costly than it should be.

The solution to all these problems is to dispense with the Lycoming, and install a proven, inexpensive, powerful, modern, extensively tested, readily available, easily maintained automotive engine that is also cheap to run to drive the Pawnee. This conversion process must be approved by the authorities, but there is a specific program to be followed which will provide certification of the modifications.

The perfect candidate for this job is the General Motors LS1 Chevrolet V8 alloy engine (better known in Australia as the Generation 3). GM have produced 8 million of these engines over the period to 2006. The company has spent billions of dollars developing, testing, refining and manufacturing it. The engine capacity is 5.7 litres. It develops 340hp at 5700rpm. It is fitted to a range of high-powered GM vehicles including the SS Commodore and Monaro. Outside of motor cars, it powers a remarkable selection of utilities, trucks, dragsters, airboats and aircraft. Complete with prop-drive unit (PSRU) it weighs in within a few kilograms of the 235 Lycoming engine. (Current production has replaced the LS1 with the L76 with 6% more capacity and 10% greater power.) It was this combination of airframe and engine the eTug syndicate decided to proceed with. In taking this course, we recognised at once that eTug would be quite different from Autotug. The immediate success of eTug encouraged Autotug to fit the same LS1 V8 engine.

It is also of the utmost importance to note here that the project to convert numbers of Pawnees in this way can only work if we, hopefully with continuing GFA support and participation, can gain relief from the CASA regulations by achieving a new class of certification for the aircraft, in the area of operation of glider towing.

The Prototype – Conversion and Advantages

The conversion of our first aircraft, VH-CUR, commenced at Bundaberg in 2005 with Dave Sharples and Ian Watson performing the work and creating the solutions to the need to accommodate water-cooling and other automotive engine peripherals within the airframe.

In an aircraft application like ours, the LS1 engine runs at about two thirds of its maximum rpm and power output. It operates on climb at 3800 to 4200 rpm, with a power output of about 250hp at the propeller. The LS1 engine is capable of running at this rate indefinitely, and has demonstrated that it can do so in numerous applications – and because our LS1s have been balanced, operation is particularly smooth. (Incidentally, the 235hp Lycoming delivers only 195hp at the propeller on climb, giving the LS1 a significant power advantage).

The engine drives a 3-bladed carbon-fibre propeller through a 2:1 reduction drive, producing propeller rotation up to 2200 rpm. At this speed we have found the engine's consumption of premium unleaded petrol to be about 25% less than a Lycoming engine. And, this is achieved with a considerable increase in launch rate. With finer tuning and propeller experimentation it is hoped to further reduce eTug's fuel consumption.

Quite apart from fuel consumption, cost savings and power advantages, there is another important benefit of a water-cooled engine. At top of climb, the pilot simply closes the throttle and descends to the field as fast as he wishes. This is because there is no shock-cooling effect to manage. In addition, the aircraft is fitted with a Tost retracting rope winch. This pulls the tow rope entirely into the fuselage, which will allow shorter approaches and improved aircraft positioning for the next tow. So with faster climb rates and considerably faster descent rates and better positioning, the turnaround time between tows is significantly reduced, enabling a minimum tows-per-hour rate of more than fourteen. Rates at Gliding Club of Victoria have been as high as fifteen.

In operational terms, the LS1 conversion offers other advantages over the Lycoming. The Pawnee is already an easy aircraft to fly and land. Along with the LS1, we are adding a number of features that will improve safety and efficiency. We are about to fit a closed-circuit TV camera to give the pilot a clear view of the glider's position and performance on tow. Improved visibility of the aircraft in flight will be provided by high-intensity strobe lights positioned above and below. The Tost retracting winch will also help simplify the pilot's landing approaches, and with the line retracted and a separate short tow line on board will make paddock landings and retrieves much simpler. The winch will also simplify the ground crew's work. A further important benefit of this winch is to eliminate the risk of unrecoverable upsets of the tug. This can happen in a conventional installation when pressures on the tow rope make it impossible to release at either end. A guillotine mechanism at the winch allows the tug pilot to cut the rope in an upset or other emergency In terms of costs, too, the statistics are persuasive. For a 6-cylinder Lycoming rebuild – say $55,000 to $65,000. For a complete replacement of an LS1 engine – under $8,000 (short engine $5,000). LS1 maintenance, too, is vastly cheaper than maintaining a Lycoming. No matter what the service intervals, the automotive engine is intrinsically cheaper to service, and has the advantage of considerably lower parts and consumables costs. With the addition of platinum spark plugs, the 100-hourly cost is limited to 6 litres of oil, an oil filter and 3 fuel filters. (With platinum plugs, EFI and no lead in the fuel, there is no plug fouling.) In service we have found oil consumption is negligible.

The advantages continue to mount: consider the noise factor. At a prop speed of 2000rpm, and with a properly muffled engine exhaust, the LS1-engined Pawnee is quieter in flight and on the ground than any equivalently powerful GA aircraft.

On the airfield, it creates considerably less erosion and impact damage because its landing rolls can be shorter and more direct, its positioning manoeuvres can be considerably shorter, and the retracted towrope will do no damage at all. The towrope itself will last very much longer than they do now.. Both of these advantages also represent cost savings to the operator – less airfield maintenance, and reduced purchasing of ropes and rings.. It is also worth noting that the winch can be readily adapted, on the spot, to a shorter towrope for use in paddock retrieves.

A final benefit – perhaps not quite as important, but a benefit nonetheless – is that using unleaded mogas will reduce the amount of lead deposited into the atmosphere, so providing a useful environmental effect as well as a 25% saving in fuel cost.

In combination, these benefits and advantages have convinced us that the LS1-engined Pawnee represents the efficient and cost-effective future of glider towing in this part of the world. This view is reinforced by the budgets for the final cost of the converted aircraft, which, once the development and prototype costs are amortised, will not exceed $45-55,000 each. (One critical issue is that this does not include development costs for Type Certification, which could be completely prohibitive unless relief is sought and granted from the Regulations.)

This estimate (minus the TC costs) is based on:

ï‚· the conversion being performed by the eTug syndicate for quality control and security of IP

ï‚· conversion of a PA-25 235, 250 or 260 minus aero engine and mount.. The PA-25 135 has not been tested for installation of an LS1. It should also be noted that Pawnees fitted with wing tanks require more complex plumbing and pump peripherals which will increase the costs slightly

ï‚· the converted aircraft delivered to the purchaser ready-to-fly at Scone, NSW.

ï‚· Is limited to engine related costs as all airframe costs are the same for LS1, or Lycoming engines

Having completed the first conversion, we are committed to certifying the aircraft, and are working with GFA to seek a specific glider tug certification category.

We named the project “enviroTug�, or eTug for short, because with its significantly reduced fuel consumption, unleaded fuel, reduced impact and erosion damage, better pilot conditions, quieter operation and considerable cost savings, it does have a friendlier environmental footprint which is worthy of note.

The bottom line advantage, though, should ultimately accrue to the clubs that fly it and the pilots who are towed by it. In aggregate, our budget comparisons and projections indicate that eTug will cut the cost of aerotows to less than half. That means twice the launches for the prices being paid now, or putting half of what pilots are spending now back in their pockets. And all with an aircraft that is built for the job, and which works the way gliding folk need it to work. The higher launch rate means one eTug will nearly do the work of two PA25-235 Lycoming engined tugs.

Financial Benefits Engine: This summary of the estimated cost savings which will result from using eTug as opposed to a Lycoming-engined PA25 is based on a 2,000 hour timeframe – the normal life of a Lycoming engine:

Fuel $ $ PA25 – Avgas at 60l/hr @ $1.75/l 210,000 eTug – Mogas at 45 l/hr @$1.30/l 117,000 Savings 93,000 Maintenance (Engine only) PA25 – Top overhaul @ $20,000 – Rebuild @ $60,000 – Total $80,000 eTug – New engine & peripherals 10,000 Savings $70,000 Extra Tows eTug - +6 tows/hr @ say $45 per tow $540,000

Total Estimated Savings with eTug per 2,000 hours $703,000 (GST excluded) It looks very much to be the right aircraft/engine for the job.

Airframe: While it is true that the costs to maintain the airframe are the same for either Lycoming, or LS1 engines, the higher launch rate of the LS1 distributes the airframe costs over a larger number of launches so creating a substantial saving per launch:

If airframe maintenance cost on average $2,200 per 100 hours the total cost over the 2,000 hours will be $44,000 and this will be distributed over many more launches than was possible with a Lycoming engine.

Progressing the Project

At the time of writing the eTug syndicate has converted our first Pawnee, VH-CUR, which has now completed over 500 engine hours. The conversion is a tribute to the work and experience of Dave Sharples. Dave's original creation and operation of Autotug have had a profound effect on the progress of eTug.

The syndicate's second Pawnee, PIJ, has now been bought. The syndicate also owns a second LS1 engine and three prop drive units. We have had approaches from three clubs in Australia and two in NZ who are interested in talking to us about Pawnee conversions for them. However, until the rules are changed to allow eTug to be certified, these conversions can not proceed.

Gaining GFA's support and active involvement in lobbying CASA to create a new class of restricted certification for the Pawnee/LS1 configuration for glider towing would speed this process immeasurably. In fact, active support from GFA in this effort is probably essential.

The eTug Group Sydney

[Craig Funston[_3_]]

On Thursday, August 1, 2013 at 11:30:08 AM UTC-7, Tony wrote:
> http://www.wired.com/autopia/2013/07/cng-airplane/
>
> could be perfect for a club towplane since we fuel up at the club field 99.9% of the time.

Thanks for the work on this aircraft and the write-up sharing your experiences. I'm curious what's happened in the 5 years since this was posted. Has there been any further learning about the aircraft and has there been any news on certification?

Best regards,
Craig Funston

[Dan Marotta]

That's very interesting, but I have a question.Â* I've learned from
watching car shows on TV that converting an older engine designed to run
on leaded fuels to run on unleaded fuels requires the cylinder heads to
be removed and new, harder valve seats to be installed.Â* It seems that
one of the uses for lead in the fuel is to cushion the valve seats
against being beaten to death by the valves.Â* I wonder if similar would
need to be addressed by switching from leaded fuel to natural gas.

Heck, as long as I'm asking, I wonder about the auto gas STCs issued for
aviation engines.Â* Maybe they're built originally with harder valve seats.

Can anyone give a good answer?

On 10/16/2018 12:54 PM, Craig Funston wrote:
> On Thursday, August 1, 2013 at 11:30:08 AM UTC-7, Tony wrote:
>> http://www.wired.com/autopia/2013/07/cng-airplane/
>>
>> could be perfect for a club towplane since we fuel up at the club field 99.9% of the time.
> Thanks for the work on this aircraft and the write-up sharing your experiences. I'm curious what's happened in the 5 years since this was posted. Has there been any further learning about the aircraft and has there been any news on certification?
>
> Best regards,
> Craig Funston

--
Dan, 5J

[Craig Funston[_3_]]

On Tuesday, October 16, 2018 at 12:19:58 PM UTC-7, Dan Marotta wrote:
> That's very interesting, but I have a question.Â* I've learned from
> watching car shows on TV that converting an older engine designed to run
> on leaded fuels to run on unleaded fuels requires the cylinder heads to
> be removed and new, harder valve seats to be installed.Â* It seems that
> one of the uses for lead in the fuel is to cushion the valve seats
> against being beaten to death by the valves.Â* I wonder if similar would
> need to be addressed by switching from leaded fuel to natural gas.
>
> Heck, as long as I'm asking, I wonder about the auto gas STCs issued for
> aviation engines.Â* Maybe they're built originally with harder valve seats.
>
> Can anyone give a good answer?
>
> On 10/16/2018 12:54 PM, Craig Funston wrote:
> > On Thursday, August 1, 2013 at 11:30:08 AM UTC-7, Tony wrote:
> >> http://www.wired.com/autopia/2013/07/cng-airplane/
> >>
> >> could be perfect for a club towplane since we fuel up at the club field 99.9% of the time.
> > Thanks for the work on this aircraft and the write-up sharing your experiences. I'm curious what's happened in the 5 years since this was posted. Has there been any further learning about the aircraft and has there been any news on certification?
> >
> > Best regards,
> > Craig Funston
>
> --
> Dan, 5J

Hi Dan, I was asking about the LS1 powered Pawnee. That's a modern engine designed to run on unleaded fuel with or without ethanol.

I may have missed other parts of the discussion related to alternate fuels and certified aircraft engines. If not it would be nice to have discussions about the use of mogas in STC'd engines in another thread.

Thanks,
Craig

[Steve Leonard[_2_]]

On Tuesday, October 16, 2018 at 2:36:58 PM UTC-5, Craig Funston wrote:
>
> Hi Dan, I was asking about the LS1 powered Pawnee. That's a modern engine designed to run on unleaded fuel with or without ethanol.
>
> I may have missed other parts of the discussion related to alternate fuels and certified aircraft engines. If not it would be nice to have discussions about the use of mogas in STC'd engines in another thread.
>
> Thanks,
> Craig

Craig just wants the LS1 powered Pawnee so he can run the airconditioner to keep cool while towing. Don't blame you one bit!

Steve Leonard

[Charlie M. (UH & 002 owner/pilot)]

To sorta answer this, there is an ongoing push by AOPA and other groups along with the FAA (in the US) for a suitable unleaded fuel for use in the older "leaded fuel" engines.
I know we added a supplement to our low lead fuel for our towplanes. Don't remember the name of it.

As to using auto derived engines for aircraft duty, sheesh, other than endurance racing (likely max runtime until rebuild, maybe 25hrs?), auto engines were not designed to run near full power for about 2000hrs before rebuild.
While most piston aircraft engine are rather archaic compared to modern auto engines, they are rather dirt simple and last for a long time at high power loads.
Yes, a better ignition system can help, although try getting that certified.
Yes, in the US, and other countries, there is a push to find a suitable unleaded fuel.
Aviation is still a small niche market (a bit larger than sailplanes, but still small for Shell, BP, Exxon, etc.), so what do they care about losing us due to environmental concerns?

There have been discussions on Subaru forums about peeps wanting 300hp+ from a 2.5L NA Subaru engine for aero use.
Yes, can be done, but at what cost?
Most is in the experimental arena.

As to going LPG, it usually is a big drop in power due to the lower power density of the fuel compared to gasoline, leaded or unleaded.

Really hard to beat gasoline for now. Anywhere close is big money to get there.

Hey, I am all for innovation, yes, we need to move from leaded fuel, but there are tradeoffs.
Just ask the peeps that get ethanol blends for cars based on season. There is a MPG drop because of it. The little performance gain due to ethanol cooling is more than offset (thus far) by the lower power density of the fuel.
This is more common in northern bits of the US, especially in metro areas (I am in the NY metro area).
I log my fuel mileage, I can tell when fuel stations go from summer blend to winter blend. It averages 15% drop in mileage.

[Tony[_5_]]

I was flabbergasted when I saw the Corvette powered Pawnee at Narromine, and they didn't have air conditioning!

[Craig Funston[_3_]]

On Tuesday, October 16, 2018 at 2:42:22 PM UTC-7, Tony wrote:
> I was flabbergasted when I saw the Corvette powered Pawnee at Narromine, and they didn't have air conditioning!

Hey, a two place V8 powered Pawnee with AC would be one sweet ride!

[Martin Gregorie[_6_]]

On Tue, 16 Oct 2018 13:13:58 -0700, Charlie M. (UH & 002 owner/pilot)
wrote:

> To sorta answer this, there is an ongoing push by AOPA and other groups
> along with the FAA (in the US) for a suitable unleaded fuel for use in
> the older "leaded fuel" engines.
> I know we added a supplement to our low lead fuel for our towplanes.
> Don't remember the name of it.
>
Slightly off topic, but how do you guys like this engine conversion?

https://www.youtube.com/watch?v=loy2n8s_l00

The airframe is interesting: it was developed in California as a low-cost
counter-insurgency aircraft, but never caught on. The design was bought
by a NZ outfit and redeveloped as an agricultural plane in, I think, the
early '60s. It originally had 250hp, but was rapidly upgraded to a 400hp
Continental flat 6. Now they either have a 750 shp turbine or, line this
one a big block truck V8. I don't know if its burning petrol or diesel.

You see one or two 750hp turbine derivatives (the PAC750 bush plane)over
here in the hands of jump clubs. They like them because the carry a lot
of jumpers at a time and can manage 2500 fpm descent rates, so the turn-
round time is good.

Back on topic: I've not heard of them being used as tow planes, but I
reckon they'd be a match for the big turbine Zlins at that game.

Anyway, enjoy the video and its V8 sound track !


--
Martin | martin at
Gregorie | gregorie dot org

[JS[_5_]]

On Tuesday, October 16, 2018 at 4:20:17 PM UTC-7, Martin Gregorie wrote:
> On Tue, 16 Oct 2018 13:13:58 -0700, Charlie M. (UH & 002 owner/pilot)
> wrote:
>
> > To sorta answer this, there is an ongoing push by AOPA and other groups
> > along with the FAA (in the US) for a suitable unleaded fuel for use in
> > the older "leaded fuel" engines.
> > I know we added a supplement to our low lead fuel for our towplanes.
> > Don't remember the name of it.
> >
> Slightly off topic, but how do you guys like this engine conversion?
>
> https://www.youtube.com/watch?v=loy2n8s_l00
>
> The airframe is interesting: it was developed in California as a low-cost
> counter-insurgency aircraft, but never caught on. The design was bought
> by a NZ outfit and redeveloped as an agricultural plane in, I think, the
> early '60s. It originally had 250hp, but was rapidly upgraded to a 400hp
> Continental flat 6. Now they either have a 750 shp turbine or, line this
> one a big block truck V8. I don't know if its burning petrol or diesel.
>
> You see one or two 750hp turbine derivatives (the PAC750 bush plane)over
> here in the hands of jump clubs. They like them because the carry a lot
> of jumpers at a time and can manage 2500 fpm descent rates, so the turn-
> round time is good.
>
> Back on topic: I've not heard of them being used as tow planes, but I
> reckon they'd be a match for the big turbine Zlins at that game.
>
> Anyway, enjoy the video and its V8 sound track !
>
>
> --
> Martin | martin at
> Gregorie | gregorie dot org

The E-Tug Pawnee VH-CUR with (backwards facing) LS1 V8 was great, but they had so many teething pains programming the chip that it didn't stick around at Keepit. Believe the E-Tug group have it all worked out now.
When I saw it, the E-Tug used a ground adjustable 4-blade prop on a PSRU made in Washington.
Climbed way too fast at first, got to 2000' before the end of the runway which is a concern at a competition.
During the period when the throttle would not go back to idle, it was shut down and landed dead stick with no shock cooling issues - but the water pump wasn't turning then either.
Believe there are newer LS- series V8s that are better.
Just found some photos from 2007.
https://www.dropbox.com/sh/0gh8y9b7pjp7yia/AADJSvfm72lYdxO-ykXOTBjEa?dl=0
Jim

[Bruce Hoult]

On Tuesday, October 16, 2018 at 4:20:17 PM UTC-7, Martin Gregorie wrote:
> On Tue, 16 Oct 2018 13:13:58 -0700, Charlie M. (UH & 002 owner/pilot)
> wrote:
>
> > To sorta answer this, there is an ongoing push by AOPA and other groups
> > along with the FAA (in the US) for a suitable unleaded fuel for use in
> > the older "leaded fuel" engines.
> > I know we added a supplement to our low lead fuel for our towplanes.
> > Don't remember the name of it.
> >
> Slightly off topic, but how do you guys like this engine conversion?
>
> https://www.youtube.com/watch?v=loy2n8s_l00
>
> The airframe is interesting: it was developed in California as a low-cost
> counter-insurgency aircraft, but never caught on. The design was bought
> by a NZ outfit and redeveloped as an agricultural plane in, I think, the
> early '60s. It originally had 250hp, but was rapidly upgraded to a 400hp
> Continental flat 6. Now they either have a 750 shp turbine or, line this
> one a big block truck V8. I don't know if its burning petrol or diesel.
>
> You see one or two 750hp turbine derivatives (the PAC750 bush plane)over
> here in the hands of jump clubs. They like them because the carry a lot
> of jumpers at a time and can manage 2500 fpm descent rates, so the turn-
> round time is good.
>
> Back on topic: I've not heard of them being used as tow planes, but I
> reckon they'd be a match for the big turbine Zlins at that game.
>
> Anyway, enjoy the video and its V8 sound track !

Yeah, that's video's been in my bookmarks for a few years.

It's hard to find newer footage and in decent quality :-(

Here's a newer model in 720p \o/ in a a two week old upload.

https://www.youtube.com/watch?v=YOTwJ1ASz1c


Oh, here's a two year old 1080p video of a classic 400 HP piston one. Looks like it's made by a model flyer who gets some stick for noise lol

https://www.youtube.com/watch?v=XSGYL3j5EXo

[Martin Gregorie[_6_]]

On Tue, 16 Oct 2018 21:40:33 -0700, Bruce Hoult wrote:

> Here's a newer model in 720p \o/ in a a two week old upload.
>
> https://www.youtube.com/watch?v=YOTwJ1ASz1c
>
Nice. Probably the best shot I've seen of a CRESCO doing its thing.
>
> Oh, here's a two year old 1080p video of a classic 400 HP piston one.
> Looks like it's made by a model flyer who gets some stick for noise lol
>
> https://www.youtube.com/watch?v=XSGYL3j5EXo

Yep, sounds like an RC guy with noise problems. I didn't realise that
there were many straight 400hp Fletchers still flying.

Do you know who did the V-8 conversions?


--
Martin | martin at
Gregorie | gregorie dot org

[[email protected]]

On Tuesday, October 16, 2018 at 3:14:01 PM UTC-5, Charlie M. (UH & 002 owner/pilot) wrote:
> To sorta answer this, there is an ongoing push by AOPA and other groups along with the FAA (in the US) for a suitable unleaded fuel for use in the older "leaded fuel" engines.
> I know we added a supplement to our low lead fuel for our towplanes. Don't remember the name of it.
>
> As to using auto derived engines for aircraft duty, sheesh, other than endurance racing (likely max runtime until rebuild, maybe 25hrs?), auto engines were not designed to run near full power for about 2000hrs before rebuild.
> While most piston aircraft engine are rather archaic compared to modern auto engines, they are rather dirt simple and last for a long time at high power loads.
> Yes, a better ignition system can help, although try getting that certified.
> Yes, in the US, and other countries, there is a push to find a suitable unleaded fuel.
> Aviation is still a small niche market (a bit larger than sailplanes, but still small for Shell, BP, Exxon, etc.), so what do they care about losing us due to environmental concerns?
>
> There have been discussions on Subaru forums about peeps wanting 300hp+ from a 2.5L NA Subaru engine for aero use.
> Yes, can be done, but at what cost?
> Most is in the experimental arena.
>
> As to going LPG, it usually is a big drop in power due to the lower power density of the fuel compared to gasoline, leaded or unleaded.
>
> Really hard to beat gasoline for now. Anywhere close is big money to get there.
>
> Hey, I am all for innovation, yes, we need to move from leaded fuel, but there are tradeoffs.
> Just ask the peeps that get ethanol blends for cars based on season. There is a MPG drop because of it. The little performance gain due to ethanol cooling is more than offset (thus far) by the lower power density of the fuel.
> This is more common in northern bits of the US, especially in metro areas (I am in the NY metro area).
> I log my fuel mileage, I can tell when fuel stations go from summer blend to winter blend. It averages 15% drop in mileage.

Wrong again, Charlie.
In the era of smallish 50-100HP auto engines in Germany in the 70's we used to flog them for many hours at full throttle on the Autobahn. They were made for this abuse and lasted just as long as those in a taxi.
Herb

[Dan Marotta]

Why are the wings bent?Â* Was the shop where it was built too small to
lay the wing flat?

On 10/16/2018 5:20 PM, Martin Gregorie wrote:
> On Tue, 16 Oct 2018 13:13:58 -0700, Charlie M. (UH & 002 owner/pilot)
> wrote:
>
>> To sorta answer this, there is an ongoing push by AOPA and other groups
>> along with the FAA (in the US) for a suitable unleaded fuel for use in
>> the older "leaded fuel" engines.
>> I know we added a supplement to our low lead fuel for our towplanes.
>> Don't remember the name of it.
>>
> Slightly off topic, but how do you guys like this engine conversion?
>
> https://www.youtube.com/watch?v=loy2n8s_l00
>
> The airframe is interesting: it was developed in California as a low-cost
> counter-insurgency aircraft, but never caught on. The design was bought
> by a NZ outfit and redeveloped as an agricultural plane in, I think, the
> early '60s. It originally had 250hp, but was rapidly upgraded to a 400hp
> Continental flat 6. Now they either have a 750 shp turbine or, line this
> one a big block truck V8. I don't know if its burning petrol or diesel.
>
> You see one or two 750hp turbine derivatives (the PAC750 bush plane)over
> here in the hands of jump clubs. They like them because the carry a lot
> of jumpers at a time and can manage 2500 fpm descent rates, so the turn-
> round time is good.
>
> Back on topic: I've not heard of them being used as tow planes, but I
> reckon they'd be a match for the big turbine Zlins at that game.
>
> Anyway, enjoy the video and its V8 sound track !
>
>

--
Dan, 5J

[Charlie M. (UH & 002 owner/pilot)]

Wrong?

Answer this, did you/others run small engines for close to 2000hrs at full throttle with no rebuilds?
Frankly, not likely.

While most IC aircraft engines are archaic, they spend most time at close to full power for close to 2000 hours.

Herb, while I know you (and you know me, but maybe not remember me), I have to say most automotive engines trying to do what a "lump of an archaic engine" is normally used in US GA gas piston engines,

Rough guess........would you run a car engine at full power for 2000hrs? Quick numbers, 45MPH for 2000 hours, say about 90,000 miles.
Me, no Frikkin way.
You, I have no clue, go for it, not my wallet.

Herb, go rush against other issues, I think you lose on this one.......OK?

[Jonathon May]

At 20:52 17 October 2018, Charlie M. UH & 002 owner/pilot wrote:
>Wrong?
>
>Answer this, did you/others run small engines for close to 2000hrs
at full
>throttle with no rebuilds?
>Frankly, not likely.
>
>While most IC aircraft engines are archaic, they spend most time
at close
>to full power for close to 2000 hours.
>
>Herb, while I know you (and you know me, but maybe not
remember me), I have
>to say most automotive engines trying to do what a "lump of an
archaic
>engine" is normally used in US GA gas piston engines,
>
>Rough guess........would you run a car engine at full power for
2000hrs?
>Quick numbers, 45MPH for 2000 hours, say about 90,000 miles.
>Me, no Frikkin way.
>You, I have no clue, go for it, not my wallet.
>
>Herb, go rush against other issues, I think you lose on this
one.......OK?
>

You can't compare aero engines with car engines,They are nearer to
boat engines in their usage .And tugs are worse.
To red line ,full throttle, a car you would need to tow a heavy load
up a very long hill for 2000hrs.
A sensible engineer would want to size the engine to run at max for
20 or 30seconds then throttle back to 50%.

Modern Motors are much more robust, but the way we are using
Rotax engines in modern tugs is going to lead to a lot of scared
tuggies making dead stick off field landings.
With a slippy tug like the Dianamic (probably spelled that wrong)
which I saw for the first time last month, with a blown Rotax and a
variable pitch prop you might have a chance .

I spent much of last year in a Duo Discus xlt behind a eurofox tug.
I am not sure who was most scared me or the Tug pilot, but it was
my syndicate partner that decided to give the sport up.

Max power is at max revs, so the prop needs to be set so that you
can reach max revs by lift off, but if that is only 65Kts you have no
choice but to tow at max revs if the glider is heavy like mine (2 fat
men a tank of gas and a fin full of water) ,and that is at a low
British pressure altitude.
I asked the salesman for a rough price for his as yet uncertified
dianamic with a vp prop ,,,about £160,000+tax,
At that price you can put a lot of gas in Pawnees

[Dave Nadler]

On Wednesday, October 17, 2018 at 6:00:07 PM UTC-4, Jonathon May wrote:
> I spent much of last year in a Duo Discus xlt behind a eurofox tug.

And that was during just one tow!

[AS]

On Wednesday, October 17, 2018 at 12:40:35 AM UTC-4, Bruce Hoult wrote:
> On Tuesday, October 16, 2018 at 4:20:17 PM UTC-7, Martin Gregorie wrote:
> > On Tue, 16 Oct 2018 13:13:58 -0700, Charlie M. (UH & 002 owner/pilot)
> > wrote:
> >
> > > To sorta answer this, there is an ongoing push by AOPA and other groups
> > > along with the FAA (in the US) for a suitable unleaded fuel for use in
> > > the older "leaded fuel" engines.
> > > I know we added a supplement to our low lead fuel for our towplanes.
> > > Don't remember the name of it.
> > >
> > Slightly off topic, but how do you guys like this engine conversion?
> >
> > https://www.youtube.com/watch?v=loy2n8s_l00
> >
> > The airframe is interesting: it was developed in California as a low-cost
> > counter-insurgency aircraft, but never caught on. The design was bought
> > by a NZ outfit and redeveloped as an agricultural plane in, I think, the
> > early '60s. It originally had 250hp, but was rapidly upgraded to a 400hp
> > Continental flat 6. Now they either have a 750 shp turbine or, line this
> > one a big block truck V8. I don't know if its burning petrol or diesel.
> >
> > You see one or two 750hp turbine derivatives (the PAC750 bush plane)over
> > here in the hands of jump clubs. They like them because the carry a lot
> > of jumpers at a time and can manage 2500 fpm descent rates, so the turn-
> > round time is good.
> >
> > Back on topic: I've not heard of them being used as tow planes, but I
> > reckon they'd be a match for the big turbine Zlins at that game.
> >
> > Anyway, enjoy the video and its V8 sound track !
>
> Yeah, that's video's been in my bookmarks for a few years.
>
> It's hard to find newer footage and in decent quality :-(
>
> Here's a newer model in 720p \o/ in a a two week old upload.
>
> https://www.youtube.com/watch?v=YOTwJ1ASz1c
>
>
> Oh, here's a two year old 1080p video of a classic 400 HP piston one. Looks like it's made by a model flyer who gets some stick for noise lol
>
> https://www.youtube.com/watch?v=XSGYL3j5EXo

Here's the whole history of this plane called the Fletcher FU-24:
http://all-aero.com/index.php/contactus/7558-pacific-aerospace-fletcher-fu-24

Uli
'AS'

[Martin Gregorie[_6_]]

On Wed, 17 Oct 2018 08:39:51 -0600, Dan Marotta wrote:

> Why are the wings bent?Â* Was the shop where it was built too small to
> lay the wing flat?
>
Keeps the tips out of the weeds while improving lateral stability :-)

We use DR400 Robins as tow planes. Like many (all?) Jodel designs, they
have flat inner wing panels and dihedralled outers. There is also a lot
of wash-out on the tip panels (shown in the side view photo on the link).
I'm told that at cruising speed the tips intentionally contribute zero
lift while minimising tip vortex drag, making them very efficient at the
design cruise speed. They're good tugs too.

We used to have a Rallye and a 235 hp Pawnee, both now replaced with a
pair of Robins.

https://en.wikipedia.org/wiki/Robin_DR400


--
Martin | martin at
Gregorie | gregorie dot org

[waremark]

"I spent much of last year in a Duo Discus xlt behind a eurofox tug.
I am not sure who was most scared me or the Tug pilot, but it was
my syndicate partner that decided to give the sport up. "

Move to a club with more powerful tugs! Or buy an Arcus M.

[Bruce Hoult]

On Wednesday, October 17, 2018 at 1:25:52 AM UTC-7, Martin Gregorie wrote:
> On Tue, 16 Oct 2018 21:40:33 -0700, Bruce Hoult wrote:
>
> > Here's a newer model in 720p \o/ in a a two week old upload.
> >
> > https://www.youtube.com/watch?v=YOTwJ1ASz1c
> >
> Nice. Probably the best shot I've seen of a CRESCO doing its thing.
> >
> > Oh, here's a two year old 1080p video of a classic 400 HP piston one.
> > Looks like it's made by a model flyer who gets some stick for noise lol
> >
> > https://www.youtube.com/watch?v=XSGYL3j5EXo
>
> Yep, sounds like an RC guy with noise problems. I didn't realise that
> there were many straight 400hp Fletchers still flying.
>
> Do you know who did the V-8 conversions?

Here's some more modern hi quality footage of the old classic. I don't know how many more years they'll be around. The 400 HP piston version has been flying for over 50 years already (and almost all the older lower powered ones converted). The first turbine one was 1967!

https://www.youtube.com/watch?v=70BAmf6ZIiw

Is it just me, or does he like to give his aileron arm a bit of a rest? I know they are reputed to be very heavy.

Another 400HP.

https://www.youtube.com/watch?v=ldWnzjcUziY

And some Cresco. Mit ze leeetle choke...

https://www.youtube.com/watch?v=7xf-ikdLqrk

[Martin Gregorie[_6_]]

On Wed, 17 Oct 2018 21:02:24 -0700, Bruce Hoult wrote:

> Another 400HP.
>
I remember that Fletchers use to have a large diameter stubby tube
pointing out and back from the rear of the cowl on both sides - must have
been around 25cm diameter maybe 30cm long. It ejected both exhaust and
cooling air, but the 400hp versions seem to be on straight stubs and with
just a flaired rear edge if the cowl for cooling air exit. Was the
tubular thing I remember only fitted to the 250hp aircraft?


--
Martin | martin at
Gregorie | gregorie dot org

[Dan Marotta]

Thanks!

On 10/17/2018 5:58 PM, Martin Gregorie wrote:
> On Wed, 17 Oct 2018 08:39:51 -0600, Dan Marotta wrote:
>
>> Why are the wings bent?Â* Was the shop where it was built too small to
>> lay the wing flat?
>>
> Keeps the tips out of the weeds while improving lateral stability :-)
>
> We use DR400 Robins as tow planes. Like many (all?) Jodel designs, they
> have flat inner wing panels and dihedralled outers. There is also a lot
> of wash-out on the tip panels (shown in the side view photo on the link).
> I'm told that at cruising speed the tips intentionally contribute zero
> lift while minimising tip vortex drag, making them very efficient at the
> design cruise speed. They're good tugs too.
>
> We used to have a Rallye and a 235 hp Pawnee, both now replaced with a
> pair of Robins.
>
> https://en.wikipedia.org/wiki/Robin_DR400
>
>

--
Dan, 5J

[[email protected]]

On Wednesday, October 17, 2018 at 3:52:56 PM UTC-5, Charlie M. (UH & 002 owner/pilot) wrote:
> Wrong?
>
> Answer this, did you/others run small engines for close to 2000hrs at full throttle with no rebuilds?
> Frankly, not likely.
>
> While most IC aircraft engines are archaic, they spend most time at close to full power for close to 2000 hours.
>
> Herb, while I know you (and you know me, but maybe not remember me), I have to say most automotive engines trying to do what a "lump of an archaic engine" is normally used in US GA gas piston engines,
>
> Rough guess........would you run a car engine at full power for 2000hrs? Quick numbers, 45MPH for 2000 hours, say about 90,000 miles.
> Me, no Frikkin way.
> You, I have no clue, go for it, not my wallet.
>
> Herb, go rush against other issues, I think you lose on this one.......OK?

Can't wait to see you cruising, descending and landing for 2,000 h on full power, Charlie. All engines have significant partial power time. I'm just fighting that old myth about GA aircraft engines (the dinosaurs of American technology) being "made" for constant max power.

[JS[_5_]]

Fred Drift:
I've towed behind a 400HP Brave, and don't recall the owner claiming it being inexpensive to operate. How does the FU-24 with IO-720 provide cheaper tows?
Chevy LS series crate engines ~400HP are 7 to 8000 dollars. How does that compare to IO-720 top and major overhauls?
Jim

[Craig Funston[_3_]]

On Thursday, October 18, 2018 at 8:05:44 AM UTC-7, JS wrote:
> Fred Drift:
> I've towed behind a 400HP Brave, and don't recall the owner claiming it being inexpensive to operate. How does the FU-24 with IO-720 provide cheaper tows?
> Chevy LS series crate engines ~400HP are 7 to 8000 dollars. How does that compare to IO-720 top and major overhauls?
> Jim

There's a popular and successful LS conversion for the Repbublic Seabee. It's also offered for other aircraft. Some versions can accommodate a reversing prop. Drop the glider and put the prop in beta to descend. Yee ha!

Here's their take on operating costs for the various engine types (including aircraft engines).

https://www.v8seabee.com/conversion-kits/operating-costs.html

Craig

[Bruce Hoult]

On Thursday, October 18, 2018 at 7:44:18 AM UTC-7, wrote:
> On Wednesday, October 17, 2018 at 3:52:56 PM UTC-5, Charlie M. (UH & 002 owner/pilot) wrote:
> > Wrong?
> >
> > Answer this, did you/others run small engines for close to 2000hrs at full throttle with no rebuilds?
> > Frankly, not likely.
> >
> > While most IC aircraft engines are archaic, they spend most time at close to full power for close to 2000 hours.
> >
> > Herb, while I know you (and you know me, but maybe not remember me), I have to say most automotive engines trying to do what a "lump of an archaic engine" is normally used in US GA gas piston engines,
> >
> > Rough guess........would you run a car engine at full power for 2000hrs? Quick numbers, 45MPH for 2000 hours, say about 90,000 miles.
> > Me, no Frikkin way.
> > You, I have no clue, go for it, not my wallet.
> >
> > Herb, go rush against other issues, I think you lose on this one.......OK?
>
> Can't wait to see you cruising, descending and landing for 2,000 h on full power, Charlie. All engines have significant partial power time. I'm just fighting that old myth about GA aircraft engines (the dinosaurs of American technology) being "made" for constant max power.

Not max, but 75%.

Tons of people are cruising around with 200 to 300 HP engines in their cars.. They occasionally use full power for five to ten seconds and then cruise along using something like 15 to 20 HP continuous.

[Nick Kennedy[_3_]]

Back in the early 2000's Parowan had a 600 HP BiPlane Ag wagon. I took a few tows in my 1958 KA6CR with that thing. Wild man JC Hutchcorne would get me to Pattern altitude before the first taxiway and often at 2000' by the end of the airstrip with a little wind. Probably burned fuel like crazy but the time under full power was very short. It seemed the tow angle was about 30 degrees, up.

[Dave Nadler]

On Friday, October 19, 2018 at 10:58:33 PM UTC-4, Nick Kennedy wrote:
> Back in the early 2000's Parowan had a 600 HP BiPlane Ag wagon.

Yup, those things were amazing.
IIRC there were 2 radial-powered Eagles there when I first visited Parawon in ~97.
Towed behind it in the whale!
https://en.wikipedia.org/wiki/Eagle_Aircraft_Eagle

[[email protected]]

Bob Carlton once towed his Salto (before he put the jet engine on it) behind Dr. Ray Vetsch's "Turbo Shark," running a Walter M601T 780 HP turbine. Climb to 6,500 AGL release altitude was about 65 seconds and they were running at the Salto's redline speed (155 knots). After twanging the release, Bob gained another 800 feet.

http://turbo-shark.com/Plane.aspx

[Nick Kennedy[_3_]]

Yup, the Eagle that's what it was.
J.C. crashed it along with just about everything else he flew there during his short time in a partnership with Dave Norwood. J.C. was a wild man Hang glider pilot from Canada as I recall. I met and flew with him in the Canadian HG Nationals in Faulklin BC.

[Dan Marotta]

That was a Grumman Ag-Cat, probably built by Schweizer, not an Ag
Wagon.Â* I towed behind it at Parowan during our first soaring safari
with my partner in our LS-6a.Â* This was before we started doing safaris
with a 1,000' rope and my truck or his car.Â* I also towed behind their
Eagle DW.1 biplane.Â* It had long, slender, tapered wings.Â* Reminded me
of a Discus.

On 10/19/2018 8:58 PM, Nick Kennedy wrote:
> Back in the early 2000's Parowan had a 600 HP BiPlane Ag wagon. I took a few tows in my 1958 KA6CR with that thing. Wild man JC Hutchcorne would get me to Pattern altitude before the first taxiway and often at 2000' by the end of the airstrip with a little wind. Probably burned fuel like crazy but the time under full power was very short. It seemed the tow angle was about 30 degrees, up.
>

--
Dan, 5J

[[email protected]]

A little thread drift here.....I flew the factory demonstrator Eagle (300hp Lycoming) back in 1980 for one little flight. While I can't attest to it's towing capabilities, I remember it was unique in that it had the long, skinny wings, and spoilers on the top of the bottom wings. Each spoiler had it's individual lever, or you could move them together. Individually, each one would help roll into a turn a bit faster, and together they would help the slightest bit if coming in over a power line. I don't recall them being particularly effective as far as being able to come down any faster from a tow, but then I was flying in the ag pilot mode, not tow pilot. I do remember it feeling like flying a big box kite.

Towing behind a turbine would be like a cat shot. Probably the same angle, but LOTS faster than a winch!

[AS]

> Towing behind a turbine would be like a cat shot. <
Maybe...

> Probably the same angle, but LOTS faster than a winch! <
Doubtful... One can easily climb at 3-4,000fpm in a winch launch. Can that tug do that even w/o a glider attached to it?

Uli
'AS'

[Martin Gregorie[_6_]]

On Sat, 20 Oct 2018 14:27:00 -0700, AS wrote:

>> Towing behind a turbine would be like a cat shot. <
> Maybe...
>
>> Probably the same angle, but LOTS faster than a winch! <
> Doubtful... One can easily climb at 3-4,000fpm in a winch launch. Can
> that tug do that even w/o a glider attached to it?
>
> Uli 'AS'

Here's the fastest and highest winch launch I've ever seen: 4500 ft on a
standard Tost winch using Dyneema rope.

While you're watching the dials go round, remember that this is a metric
glider, so the altimeter is in metres (inner markings are 1000m) and the
vario is m/sec (initial stabilised climb rate is 15 m/s or 30 kts).

http://www.youtube.com/watch?v=-VlRd9-wxQI



--
Martin | martin at
Gregorie | gregorie dot org

[Bruce Hoult]

On Saturday, October 20, 2018 at 2:27:01 PM UTC-7, AS wrote:
> > Towing behind a turbine would be like a cat shot. <
> Maybe...
>
> > Probably the same angle, but LOTS faster than a winch! <
> Doubtful... One can easily climb at 3-4,000fpm in a winch launch. Can that tug do that even w/o a glider attached to it?

In the latest version in skydiving configuration, that NZ ag plane takes 17 jumpers to 12000 ft in 10 minutes, throws them out, and gets back on the ground in 15 minutes, all up.

I imagine it would do 3000 FPM empty. And what do 17 parachutists weigh, with gear? Probably 1500 kg 3300 lb I guess. It wouldn't notice a single set glider much.

http://diverdriver.com/pac-750xl/

[Charlie M. (UH & 002 owner/pilot)]

Pretty cool writeup on the plane. Thanks for posting.

[AS]

On Saturday, October 20, 2018 at 6:28:17 PM UTC-4, Bruce Hoult wrote:
> On Saturday, October 20, 2018 at 2:27:01 PM UTC-7, AS wrote:
> > > Towing behind a turbine would be like a cat shot. <
> > Maybe...
> >
> > > Probably the same angle, but LOTS faster than a winch! <
> > Doubtful... One can easily climb at 3-4,000fpm in a winch launch. Can that tug do that even w/o a glider attached to it?
>
> In the latest version in skydiving configuration, that NZ ag plane takes 17 jumpers to 12000 ft in 10 minutes, throws them out, and gets back on the ground in 15 minutes, all up.
>
> I imagine it would do 3000 FPM empty. And what do 17 parachutists weigh, with gear? Probably 1500 kg 3300 lb I guess. It wouldn't notice a single set glider much.
>
> http://diverdriver.com/pac-750xl/


Thanks for posting that link - impressive, indeed!

Uli
'AS'