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#1
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motorgliders as towplanes
I know this has come up before in RAS. But thought I would bring up
the subject again. For a club looking at long term projections, which at some point will include either sticking a "new" engine on a Pawnee or getting rid of it, does it make sense to start evaluating getting a 2 place motorglider to serve as a tug and also as a touring/training tool? Can a MG tug pull a loaded 2 place Blanik on a standard day at SL, from a 1800' grass strip? Or perhaps such a tug could be used to tow the members single place ships, and the heavier/ 2-place ships stow behind the clubs remaining pawnee? We are blessed with 3 towplanes in our club, there are upcoming factors that will/are causing us to look at several different scenarios and am wondering if tossing a MG into the mix might be one such solution. Brad |
#2
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motorgliders as towplanes
On Mar 8, 10:03*am, Brad wrote:
I know this has come up before in RAS. But thought I would bring up the subject again. For a club looking at long term projections, which at some point will include either sticking a "new" engine on a Pawnee or getting rid of it, does it make sense to start evaluating getting a 2 place motorglider to serve as a tug and also as a touring/training tool? Can a MG tug pull a loaded 2 place Blanik on a standard day at SL, from a 1800' grass strip? Or perhaps such a tug could be used to tow the members single place ships, and the heavier/ 2-place ships stow behind the clubs remaining pawnee? We are blessed with 3 towplanes in our club, there are upcoming factors that will/are causing us to look at several different scenarios and am wondering if tossing a MG into the mix might be one such solution. Brad I recently flew a Lambada and was very impressed with it's take off and climb performance. We didn't tow any gliders so I can't report on that. I flew the 80 HP version. We were at sea level, two 200+lbs guys and only 80 HP, takeoff and climb performance seemed to be better than a Super Cub. The 80 HP version isn't used for towing but the 100 HP version is. It is reported to have about as good as a 150 HP Super Cub performance in towing. The Lambada soared pretty well, I was really impressed. The L/D is claimed to be about 30/1 and that seemed about right while gliding between thermals. It's a well thought out little machine. Check out Urban Air USA. My demo ride was with the very sailplane experienced pilot Jim Lee. Great guy and a great team. good luck, Dan |
#3
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motorgliders as towplanes
On Mar 8, 10:03*am, Brad wrote:
I know this has come up before in RAS. But thought I would bring up the subject again. For a club looking at long term projections, which at some point will include either sticking a "new" engine on a Pawnee or getting rid of it, does it make sense to start evaluating getting a 2 place motorglider to serve as a tug and also as a touring/training tool? Can a MG tug pull a loaded 2 place Blanik on a standard day at SL, from a 1800' grass strip? Or perhaps such a tug could be used to tow the members single place ships, and the heavier/ 2-place ships stow behind the clubs remaining pawnee? We are blessed with 3 towplanes in our club, there are upcoming factors that will/are causing us to look at several different scenarios and am wondering if tossing a MG into the mix might be one such solution. Brad You don't say what type of motorglider you are thinking of (seems even sustainers count as motorgliders if you believe Soaring Magazine) But having said that there is not one touring (i.e. non pylon style) motorglider I can think of that I'd want to tow behind in any sailplane, well certainly not a two place glider. A Kstana or something with a big engine might be able to tow a light glider but it is not going to touch a good Pawnee or simmilar and so what then you are left with a not great tug and a not very good XC trainer (or XC anything). But I don't understimate how the appeal of being flexible/ multi-purpose and doing something clever/different might just suck people in... As a self-launch motorglider owner in general I tend to think good XC trainers do *not* have motors. Think Duo Discus or DG-1000S class two seater. Motorgliders are compelx and expensive to operate and most have more vices than a modern two-seater, so you are not going to let newer pilots (the very ones you want to be encouraging to go XC) go fly them solo etc. And if you only do dual in that glider and send them solo in an a conventional glider you are sending the XC student/ mentoree a very bad signal. Motorgliders can be great for some things, inluding orientatiion flights, etc. but you can also do those in a two place power plane. Darryl |
#4
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motorgliders as towplanes
We spent quite some time looking at this. We currently have 2xPawnee 235's
and a Super Cub 180. We also have a Falke 2000 motorglider. Normally we only need on tug, except on busy periods when we occationally need two. The motorglider is underutilised, so the idea of a motorglider that can tow seemed attractive. To keep operations simple, we assumed that one of our Pawnees would be servicable, so that the Motorglider could tow single seaters (which is usually the cause of our peak demand), and therefore the utilisation of the motorised fleet would increase and we would need one less aircraft. Initially we evaliated the 100hp fixed pitch Rotax Falke. It did tow, but seemed a bit marginal from our operation. Also it needed careful management of the engine temperature to avoid long term issues. Then we looked at the Grob 109 Turbo. This gives about 130hp for the initial takeoff and was substantially better than the Falke whilst still delivering economy which was more than two times better than the Pawnee. I would say that it was the best we looked at and also better than the super dimona, which we also studied briefly. In the UK a G109T has been towing from a grass strip for almost two years now, towing a variety of single and two seat gliders (including duo's etc) and has very few problems, I understand. The concept is certainly worth considering. In the meantime, we continue to watch developments, as well as plans to re-engine Pawnees with 230hp Diesel Engines. Craig Lowrie, UK At 17:28 08 March 2009, Darryl Ramm wrote: On Mar 8, 10:03=A0am, Brad wrote: I know this has come up before in RAS. But thought I would bring up the subject again. For a club looking at long term projections, which at some point will include either sticking a "new" engine on a Pawnee or getting rid of it, does it make sense to start evaluating getting a 2 place motorglider to serve as a tug and also as a touring/training tool? Can a MG tug pull a loaded 2 place Blanik on a standard day at SL, from a 1800' grass strip? Or perhaps such a tug could be used to tow the members single place ships, and the heavier/ 2-place ships stow behind the clubs remaining pawnee? We are blessed with 3 towplanes in our club, there are upcoming factors that will/are causing us to look at several different scenarios and am wondering if tossing a MG into the mix might be one such solution. Brad You don't say what type of motorglider you are thinking of (seems even sustainers count as motorgliders if you believe Soaring Magazine) But having said that there is not one touring (i.e. non pylon style) motorglider I can think of that I'd want to tow behind in any sailplane, well certainly not a two place glider. A Kstana or something with a big engine might be able to tow a light glider but it is not going to touch a good Pawnee or simmilar and so what then you are left with a not great tug and a not very good XC trainer (or XC anything). But I don't understimate how the appeal of being flexible/ multi-purpose and doing something clever/different might just suck people in... As a self-launch motorglider owner in general I tend to think good XC trainers do *not* have motors. Think Duo Discus or DG-1000S class two seater. Motorgliders are compelx and expensive to operate and most have more vices than a modern two-seater, so you are not going to let newer pilots (the very ones you want to be encouraging to go XC) go fly them solo etc. And if you only do dual in that glider and send them solo in an a conventional glider you are sending the XC student/ mentoree a very bad signal. Motorgliders can be great for some things, inluding orientatiion flights, etc. but you can also do those in a two place power plane. Darryl |
#5
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motorgliders as towplanes
On Mar 8, 1:03*pm, Brad wrote:
I know this has come up before in RAS. But thought I would bring up the subject again. For a club looking at long term projections, which at some point will include either sticking a "new" engine on a Pawnee or getting rid of it, does it make sense to start evaluating getting a 2 place motorglider to serve as a tug and also as a touring/training tool? Can a MG tug pull a loaded 2 place Blanik on a standard day at SL, from a 1800' grass strip? Or perhaps such a tug could be used to tow the members single place ships, and the heavier/ 2-place ships stow behind the clubs remaining pawnee? We are blessed with 3 towplanes in our club, there are upcoming factors that will/are causing us to look at several different scenarios and am wondering if tossing a MG into the mix might be one such solution. Brad I remember reading about a Pipistrel Sinus motorglider towing an LS8 to 2400 feet AGL in 6 minutes in Italy............. I assume that a lighter gliders should climb even better! There is also a video on Youtube showing a Lambada motorglider towing a double seater metal glider. The Sinus with an 80 HP Rotax The Lambada with a 100 HP Rotax Motorgliders will tow into the future!!!!! Maybe at 3 gallons an hour car fuel. |
#6
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motorgliders as towplanes
In Sweden it is quite common to use Super Dimonas as tugs and we tow two
seaters with no problem. Climb rate is like a 150 hp PA-18. But the ground run is a bit longer. The big advantages are less fuel consumption and that that you can tow with a gliding license only. Robert ASW 28-18E RD Brad skrev: I know this has come up before in RAS. But thought I would bring up the subject again. For a club looking at long term projections, which at some point will include either sticking a "new" engine on a Pawnee or getting rid of it, does it make sense to start evaluating getting a 2 place motorglider to serve as a tug and also as a touring/training tool? Can a MG tug pull a loaded 2 place Blanik on a standard day at SL, from a 1800' grass strip? Or perhaps such a tug could be used to tow the members single place ships, and the heavier/ 2-place ships stow behind the clubs remaining pawnee? We are blessed with 3 towplanes in our club, there are upcoming factors that will/are causing us to look at several different scenarios and am wondering if tossing a MG into the mix might be one such solution. Brad |
#7
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motorgliders as towplanes
I'm struggling with a similar question, and it relates to rebuilds. I
guess different rebuilds cost very different amounts, and it seem that a Pawnee rebuild is $35K and a little more. Could it be that a cheaper to rebuild tow plane could be a better choice? |
#8
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motorgliders as towplanes
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#9
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motorgliders as towplanes
On Sun, 08 Mar 2009 14:29:37 -0700, brianDG303 wrote:
I'm struggling with a similar question, and it relates to rebuilds. I guess different rebuilds cost very different amounts, and it seem that a Pawnee rebuild is $35K and a little more. Could it be that a cheaper to rebuild tow plane could be a better choice? Seems to me that you need to total up several factors: 1) The cost of replacing/rebuilding the tow plane 2) The cost of insuring the replacement for the time you'll keep it 3) The total operating cost for the time you'll keep it, i.e. include both overhauls/part replacement as well as fuel and oil. Then calculate the total cost per annum of each course of action. -- martin@ | Martin Gregorie gregorie. | Essex, UK org | |
#10
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motorgliders as towplanes
On Mar 8, 3:23*pm, Martin Gregorie
wrote: On Sun, 08 Mar 2009 14:29:37 -0700, brianDG303 wrote: I'm struggling with a similar question, and it relates to rebuilds. I guess different rebuilds cost very different amounts, and it seem that a Pawnee rebuild is $35K and a little more. Could it be that a cheaper to rebuild tow plane could be a better choice? Seems to me that you need to total up several factors: 1) The cost of replacing/rebuilding the tow plane 2) The cost of insuring the replacement for the time you'll keep it 3) The total operating cost for the time you'll keep it, i.e. include * *both overhauls/part replacement as well as fuel and oil. Then calculate the total cost per annum of each course of action. -- martin@ * | Martin Gregorie gregorie. | Essex, UK org * * * | SO let's make it an even dozen. Some other things that apply to all choices (including the Pawnee...) 4) who will maintain the tow plane, what experience on type/model do they have and how many others doing similar things are available to learn/get help from? 5) Vendor/product risk - a risk factor for chance the vendor will go out of business or there will be a nasty AD etc. (yes nastier than the spar mounts on Pawnee, and yes this risk applies to Pawnees etc. as well) 6) Parts risks/costs - for some models where the vendor is no longer making them, what is the risk parts won't be available, will be hard to find or will be expensive to fabricate if at all possible? (And yes this risk applies to Pawnees etc. as well, but is reduced somewhat by their wide use) 7) Operational limitations - find out how whatever you are looking at tows on the days you need to, on the surfaces, at the temperatures and density altitudes etc. (e.g. more than a few motor gliders have cooling issues when it gets hot outside). 8) The expected TBO of the engine - I'd be pretty cautious about assuming anything based on published TBOs - in general and especially if the motorglider is towing. I'd go talk to real owners who have been doing something similar. I have a lot less confidence in the engines in some of these motorgliders doing as well there say compared to a Lycoming in a Pawnee - but that is just my bias, unconfirmed by reality either way. Bear in mind that with towing you may be putting a lot more time on the engine than others so you'll be the canary in the coal mine. 9) The utility at all of the motorglider as a XC glider/training glider (you may just maintain it as a tow plane). 10) Insurance costs, pilot experience requirements and other issues. I have no idea there, but I'd be calling my insurance agent early on in the process (like now). Especially if some of the desire is to get glider pilots with a motorglider endorsement towing - I cringe a bit at that unless those folks have some power experience and/or a lot of time in the motorglider. 11) Experimental category issues (if it's an experimental motorglider) in the USA - I'd expect you would run into issues towing with motorglider with an contest and exhibition certification. 12) You need to know that a tow release system is available or what one involve/will cost to put through as a 337 only (if the FSDO would do that?) and what issues that involves. One of the appeals of the tow setup on many Pawnee's is the retractable tow rope. I'm guessing there may not be space to install that in many motorgliders. Anyhow just more brain food. Darryl |
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