Fauvel AV-36 and 361 project - comment page

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Hot Wings

Grumpy Cynic
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A rough data point for a hybrid system in a heavy AV-361.
15 hp ICE would provide a 65 mph cruise speed and enough left over to recharge the batteries for a 3000 foot climb every 30 minutes.

A 15 Hp pure ICE could climb at about 300ft/min at the same weight.
A 5 gallon tank at .45 lbs/hp/hr = .675 gal/hr at 65 mph = 6.9 hours or a 425 mile range (with 30 min reserve in zero lift zero wind with no additional climb phase)

...........all napkin grade calculations.;)
 

Vigilant1

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Thanks. It's hard for me to see a significant advantage in utility of the hybrid system. Did you look at the difference in weight for the (pure ICE+gasoline) vs (ICE+gasoline+generator+batteries+motors+cable)?
 

Hot Wings

Grumpy Cynic
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Did you look at the difference in weight
Not in the detail needed to actually say which is more. From the available component weights I've been able to find online the overall weight works out pretty much the same. That may all change with real parts on a real scale in the shop.

As you note there isn't as much advantage using a hybrid for the AVs as there may be for some other missions. The real advantage is in the packaging. I'm not real pleased having 80 pounds of metal 6 inches right behind my back knowing how little crush structure there is in the AVs. Being able to move some of those parts down and distributing the masses might help during a crash? Finding room for a BRS will be easier as well.
 

blane.c

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And it could work direct drive unlike a lot of the model electric motors that spin too fast. I also like the fact that they are using more voltage than the model motors.
I do have a problem dealing with companies that don't publish their prices. :(
I wrote him a couple years ago. He seems reasonable to me. They want to sell the whole package of course motor, controller and batteries. It may be a good Idea to get a price from them, you can always say no. I was looking around for something like Dale Kramer's set up at the time since Roby backed out of the market. I think Roby is working with Toyota now and also Emrax.

I would ask about hollow shaft, with a hollow shaft you can get prop controls to the front side of the propeller. If not interested now maybe in the future.
 

blane.c

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For 2 more cents, in a glider just go straight electric. Keep it light so it is still really a glider. So minimal batteries and a way to regenerate, not that you will get great efficiency regenerating but you'll get something back. I don't think it knocks the price of the controller up that much and you'll probably want to use the drag from the prop anyway as it is not detrimental to a motor the way it is to an engine.
 

blane.c

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The thing about li-po batteries as I understand it is matching "internal resistance" (ir). So even the best battery li-po cells are manufactured with some difference in the ir and those that buy a lot of cells can sort the cells and put the cells with matching ir into the same battery pack. This produces a better quality battery pack, and is likely the difference between the premium and lesser cost battery packs from the battery dealers. Battery life and ir are tied together and so battery packs with a lower ir will last longer provided they are properly taken care of. HOW FAST YOUR MOTOR WILL SPIN is also tied to ir. Of course ir isn't listed on the battery.

This is expounded better here.

https://rogershobbycenter.com/lipoguide/

I just think this is a clean looking electric.

 

blane.c

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Well it is a China motor beware. I think China builds good stuff too but they will sell what the market will bear. Caveat Emptor.
 

jarnicoton

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I logged four flights with a AV-36 in 1971 at Reims-Prunay (LFQA), one soaring and three shorter.
Big psychological problem : the glider usually never flown, pilots preferring stay on the ground and not take-off with that. They accused the machine to have the glide ratio of a X-15 (no space shuttle then) and the sink rate of a stone. They were simply afraid !

I volunteered, considering that my chance to die in a machine over 100 of wich had flown, was a little one.
Problem : very unpleasant and difficult to handle on the ground between hangar and runway ; need of a special towing cable with two hooks.

Very narrow cockpit plus two large spaces for the elbows in the wing roots ; terribly narrow canopy where my glasses hit the plexiglas if I turned the head left or right. Today, thanks to the cataract surgery, no longer myopia nor googles.
Glide ratio a little under 25, sink rate about 3 ft/s. Not surprisingly : normal roll, quite touchy elevators (but not uncomfortable) and sluggish rudders.
No wheel, no pitch inertia and no elevator "volume" : frequent terrible landings (grass only) with three our four bounces.

Conclusion : funny but no real advantages. Maybe fast to built.
 
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Hot Wings

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Thanks for the post.
Your experience seems to be pretty much in line with the other pilot reports I've read.
Many of the noted dislikes are being addressed with the 361 MK II version. Some, like the fuselage and canopy volume, are easy to fix with a high degree of confidence in the outcome. Others will have to wait for real world flight to evaluate fully.
 
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