Eagler's Nest
Airframes => Double Seaters => Topic started by: ToddK on January 09, 2016, 12:12:09 PM
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Hey guys,
I was looking the valley Engineering Big twin. It's making 40hp power swinging a 70x40 prop and producing 250 lbs of static thrust.
I am guessing that the Big Bad Twin 50hp version would preform even better and burns 2 gal per hour.
Everything I have read about the 60 hp vw engines is that they turn a smaller prop and put out about 200 lbs of static thrust.
It seems to me that the Big Bad Twin with 10 fewer hp but a prop disc nearly 20% larger then the 60hp VW would be a good power plant for double eagle, and would shave a lot of weight off.
Am I missing something?
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I have a 2200cc 4cyl 80hp and Franks Propellor 62 inch
1: Prop only has 5in clearance to ground 70 inch wont work ( need 5in clearance at a bear min )
2: Extremely happy with my 80hp / prop combo and would not change it ( Frank nailed the prop choice )
Flew today to test max weight - total at flight was 1040lb and hate to see what a 60hp plane would fly like
(see number 2)
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I agree with you on the 990 Generac engine from valley engineering...Wish someone who knows more than us would commit on this subject. Paran Wings
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I just got off the phone with Valley Engineering, and they said that their 50hp motor turning the larger prop will outperform the 60 hp direct drive vw, and it does so with a pretty significant weigh savings at only 2 gal per hour. Sounds like a good way to clear up some of the those weight and balance concerns featured above. I asked about vibration, and they said as they mount it (metal to metal bead mount) it would be more then a VW and less then a Rotax two stroke. Putting it on rubber mounts makes it very smooth. I guess a bit more gear will be necessary for the larger prop.
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I'm definitely interested in the big bad twin. I'm no where near the engine stage yet, but this engine intrigues me. I may look into using this. You would just have to make your landing gear a 4 or 5 inches taller. You would also have to raise the tail wheel to keep the same angle.
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I contacted valley engineering today and was told the 50hp big bad twin will not be powerful enough for the cabin eagle, therefore i will not be using this engine.
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If you have 12K plus to spend here is a promising engine...
http://www.d-motor.eu/nl/lf26-36.htm (http://www.d-motor.eu/nl/lf26-36.htm)
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Whether the power is there or not for the model aircraft you are building, do keep in mind there is a significant offset, especially in a belt type re-drive. You may not need to extend the gear as much or at all. Always a good idea to plan through that regardless of engine choice.
These eagles are designed with a shorter (VW) prop in mind. anything different should be investigated.
Extending your gear should also include consideration for added bracing on the gear legs.