ASH-25E + Rotax 275

[Willy VINKEN]

ASH-25E - Rotax 275

Having flown some of them, I noticed a couple of recurrent problems:

1. Actuator cannot start to lift the engine out of its well.
The usefull lever to start moving is short...
Manually opening the hatch helps. Door sandows are original.
Battery voltage is OK (a car battery has been tried).
Screw actuator has been opened, cleaned and properly lubricated.
800N gasstrut has been replaced with a 1000N new one.
Anyone got rid of this problem?

2. What is the safest way to get and keep propeller vertical while
lowering the engine?
I've seen (lucky) pilots rely on the 'natural' stop position after
switching off.
I've also seen two propellers shattered while trying to enter the
fuselage...
Some engines have a magnetic position detector on the flywheel.
Some pilots use a mirror to see the propeller.
Some position it with wind-and-brake, some have a manual starter
cable.
Some brakes on the flywheel seem really efficient, some are slippery.
Anyone has bright ideas?

[Eric Greenwell]

Willy VINKEN wrote:
> ASH-25E - Rotax 275
>
> Having flown some of them, I noticed a couple of recurrent problems:
>
> 1. Actuator cannot start to lift the engine out of its well.
> The usefull lever to start moving is short...
>
You should also post a question on this newsgroup:

http://groups.yahoo.com/group/ASA-NewsGroup/

--
Eric Greenwell - Washington State, USA (netto to net to email me)

- "Transponders in Sailplanes - Feb/2010" also ADS-B, PCAS, Flarm http://tinyurl.com/yb3xywl

- "A Guide to Self-launching Sailplane Operation Mar/2004" Much of what you need to know tinyurl.com/yfs7tnz

[cernauta]

On Sun, 18 Apr 2010 09:34:34 +0200, Willy VINKEN
> wrote:

>I've seen (lucky) pilots rely on the 'natural' stop position after
>switching off.

>Some brakes on the flywheel seem really efficient, some are slippery.
>Anyone has bright ideas?

I have a DG600M, so a different system, built around the same engine.
The propeller must be installed in such a way that one of the blades
finds the max. piston compression a few degrees (10-20°) before the
ideal vertical position. It's impossible to have both blades set for
the same condition. You will have to paint or "mark" the reference
blade.

The propeller brake works quite well, provided the lining material and
the metal disc surface (flywheel) are both oil-free.
If necessary, renew or resurface the lining after accurate degreasing
of the flywheel's braking surface.

Aldo

[Willy VINKEN]

On Mon, 19 Apr 2010 14:24:21 +0200, cernauta > wrote:

>On Sun, 18 Apr 2010 09:34:34 +0200, Willy VINKEN
> wrote:
>
>>I've seen (lucky) pilots rely on the 'natural' stop position after
>>switching off.
>
>>Some brakes on the flywheel seem really efficient, some are slippery.
>>Anyone has bright ideas?
>
>I have a DG600M, so a different system, built around the same engine.
>The propeller must be installed in such a way that one of the blades
>finds the max. piston compression a few degrees (10-20°) before the
>ideal vertical position. It's impossible to have both blades set for
>the same condition. You will have to paint or "mark" the reference
>blade.
>
>The propeller brake works quite well, provided the lining material and
>the metal disc surface (flywheel) are both oil-free.
>If necessary, renew or resurface the lining after accurate degreasing
>of the flywheel's braking surface.
>
>Aldo


Fine, Aldo.
I tried to work it out with the angles, but I don't have the precise
reductor ratio.
Say we have a 3:1 reduction: the full compression (TDC) will be
encountered only once every 3 revolutions, right?
I guess the TDC+~15° reference is chosen because it's easier to feel
than near BDC.
Which means the propeller would stop after another 180°, when the
piston is at BDC+~15°, and compression starts to build up.
It's difficult for me to rely on the assumption that the propeller
will always stop turning near (enough) this precise position.
Does yours?
Also, it should be hazardous to check it on the ground, because
there's no relative wind...
And if my above assumption is correct, I guess the brake's only task
is to prevent the low compression to turn back the propeller when it
is lowered out of wind pressure?

Willy

[cernauta]

On Mon, 19 Apr 2010 17:07:25 +0200, Willy VINKEN
> wrote:

>Fine, Aldo.
>I tried to work it out with the angles, but I don't have the precise
>reductor ratio.
>Say we have a 3:1 reduction:

that's correct, at least on the 600. I'm pretty sure it's the same for
the 25.

>the full compression (TDC) will be
>encountered only once every 3 revolutions, right?

3 rev of the engine, 1 rev of the propeller.

>I guess the TDC+~15° reference is chosen because it's easier to feel
>than near BDC.

correct. At or near TDC, you feel the compression as you move the
propeller by hand.

>Which means the propeller would stop after another 180°, when the
>piston is at BDC+~15°, and compression starts to build up.

I'm not following you in this.
The propeller will stop (or, slow down to almost a stop) at the
beginning of a compression cycle. That has a 1 out of 3 chance of
being the desired, near vertical position.

>It's difficult for me to rely on the assumption that the propeller
>will always stop turning near (enough) this precise position.
> Does yours?

1 of the 3 positions. Then you just wait for it to pass along the
wrong compression zone(s), and as it approaches the one very close to
vertical, you must be ready to pull firmly on the propeller brake.
I guess you have a rear view mirror.

>Also, it should be hazardous to check it on the ground, because
>there's no relative wind...

On the ground, you just need to move the prop by hand, and make sure
one blade (in my case, the one related to the magnetic proximity
sensor) hits compression about 10-20 cm before vertical (measured at
the tip).
The proximity sensor gives "consensus" to the electric retraction
system, provided the main switch is in "normal operation mode". In
Manual mode, I can retract the engine in whichever prop position
(accepting high risk of damage to the prop and the engine-bay lids)

>And if my above assumption is correct, I guess the brake's only task
>is to prevent the low compression to turn back the propeller when it
>is lowered out of wind pressure?

The brake prevents the propeller to move, though slowly, due to the
relative wind. Without the brake, at 90 km/h, the prop will win over
the compression in a few seconds.

Aldo



>
>Willy

[[email protected]]

Am Sonntag, 18. April 2010 09:34:34 UTC+2 schrieb Willy VINKEN:
> ASH-25E - Rotax 275
>
> Having flown some of them, I noticed a couple of recurrent problems:
>
> 1. Actuator cannot start to lift the engine out of its well.
> The usefull lever to start moving is short...
> Manually opening the hatch helps. Door sandows are original.
> Battery voltage is OK (a car battery has been tried).
> Screw actuator has been opened, cleaned and properly lubricated.
> 800N gasstrut has been replaced with a 1000N new one.
> Anyone got rid of this problem?
>
> 2. What is the safest way to get and keep propeller vertical while
> lowering the engine?
> I've seen (lucky) pilots rely on the 'natural' stop position after
> switching off.
> I've also seen two propellers shattered while trying to enter the
> fuselage...
> Some engines have a magnetic position detector on the flywheel.
> Some pilots use a mirror to see the propeller.
> Some position it with wind-and-brake, some have a manual starter
> cable.
> Some brakes on the flywheel seem really efficient, some are slippery.
> Anyone has bright ideas?

Hey, I am also flying a ASH25E and now worked through all the mentioned problems and now the engine is extremely reliable and easy to handle.
Measure your voltage directly at the actuator for lifting the engine. My Battery was ok and also had a 1200N gasstrut and didn´t manage to lift the hatch.
From your battery, put a really thick cable (at least 4mm²) from your + directly to the Relais. The problem is that the actual cable and wiring from Binder isn´t the best. you have corrosion, multiple connectors, and small diameter for the cables which run to the main switch in the front panel and then back to the engine compartment --> Lots of voltage loss. My actuator only got 5V from the original 15V of the battery.
Now with this new cable the prop basically 'jumps' out of the engine compartment.

Additionally, I strongly recommend installing a starter to the rotax 275. There is a STC from Binder for the installation and you can also get the parts there. With that system it takes you like 15s and 30m loss of height to start your engine without stress in the air and additionally you are able to start the engine easily at the ground (e.g. for testing or push-pull).

As also mentioned with the braking of the propeller, you have to mount it in a way that it is a couple of centimeter before the actual compression of the motor. then the brake will be able to hold the propeller in place.

Shoot me a mail if you have questions. Happy to help!
Great glider, so worth putting some (Rather small) effort into the engine to make it reliable and usable!

Thanks
Markus

[john firth]

On Sunday, April 18, 2010 at 3:34:34 AM UTC-4, Willy VINKEN wrote:
> ASH-25E - Rotax 275
>
> Having flown some of them, I noticed a couple of recurrent problems:
>
> 1. Actuator cannot start to lift the engine out of its well.
> The usefull lever to start moving is short...
> Manually opening the hatch helps. Door sandows are original.
> Battery voltage is OK (a car battery has been tried).
> Screw actuator has been opened, cleaned and properly lubricated.
> 800N gasstrut has been replaced with a 1000N new one.
> Anyone got rid of this problem?
>
> 2. What is the safest way to get and keep propeller vertical while
> lowering the engine?
> I've seen (lucky) pilots rely on the 'natural' stop position after
> switching off.
> I've also seen two propellers shattered while trying to enter the
> fuselage...
> Some engines have a magnetic position detector on the flywheel.
> Some pilots use a mirror to see the propeller.
> Some position it with wind-and-brake, some have a manual starter
> cable.
> Some brakes on the flywheel seem really efficient, some are slippery.
> Anyone has bright ideas?

My PIK 20E has a retrofited engine detent that is very good; a notched plate
is bolted to the flywheel, a spring loaded arm has a finger which engages with the notch when the engine doors are OPEN; I added a microswitch controlling a red LED on the panel. The system only works if the reduction ratio is 2:1 so the prop is vertical every engine revolution.

1. Stop the engine
2. Open the doors to enable the sprung arm.
3. Wait for the light to go out.( there is a clunk as the detent engages.
4. retract the engine 80%.
5 climb in the thermal.
6. fully retract the engine and close the doors.

Much easier than fiddling with a brake and mirror.

John Firth