Jaketab

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It appears that Desert Aircraft and 3W are releasing new 85cc engines this month. I'm considering pairing a 33% WH Extra 260 with one of these engines. The question is - are these engines heavy enough to balance the plane and powerful enough to comfortably fly the plane in 3D.

The DA-85 is advertised at about 4.54 pounds with ignition. The 3W-85xi is about 5.05 pounds? My greatest concern is that the plane may be too tail heavy with one of these new engines and require substancial tail weight.

Thoughts from Tom or anyone please regarding engine choice for the 33% Extra 260.

Thanks - Jaketab

krayzc-RCU

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Man I saw that DA-85 in action at J. Nall yesterday man it was strong from the word go remember a 85cc engine is close in cc to a 100-106 DA or 3W powerhouse. The flyers I send that had them were running 26 x 10 and 27 x 10 props. I saw one take off an go verticle for at least 1000 feet. I could not belive this thing was moving on an unline so fast. Now the details of the plane and weight I have no idea as J.Nall has so much to catch you eye if you have been there b4.

jaredge

Either will be a great choice. I had one with a ZDZ80rv, lighter than both (I think?) . No trouble at all balancing, actually moved the batterys to the back of the hatch area, one servo on rudder mounted in the tail on push pull. Had slight push on elevator on inverted 45 to maintain heading. Good combo, the newer ones with more power should be even better.

Jared

dryverman

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I have the 33% WH Edge 540 with a BME 105 [5.2 lbs]. Balance
was perfect with this lightweight engine. Either of the engines you
are considering should be fine in the 260.
BTW...these 33% WH's are AWESOME planes for for the $!!!

Roger

erikpmort

My Feedback: (52)

you need a big engine to balance the plane. i'm putting one together right now with an 80xi and i'm going to have to put 2 rudder servos in the tail to make it balance out. your other option is to use the shortest standoffs possible and move the cowl back further by drilling new holes etc... you asked a good question in advance.

rctom

I think Erik meant to say that a little differently.

With the DA-85 it shold be killer.

I originally designed the Extra 260 so it would be possible to balance with a BME 110, and so it would be dead on with something like a ZDZ-80. A DA-85 will be perfect and will be like a rocket.

TF

rcairflr

My Feedback: (44)

I also originally had a 3W-80xi on my Extra 260.. 1 JR 8611A on the tail for rudder. Mounted the ignition battery just in front of the wing tube and 2 receiver batteries mounted as far back as possible on the rudder servo tray. Airplane balanced at 4.1 inches back as measured on the wingtip. If I would of had more room the batteries would have gone farther back. So in answer to your question the airplane should balance easily with either engine. BTW, I felt that the standard 3W-80xi was not enough power. If you are going to go with the 3W-85 I would install the competition series to make sure there is ample power. Right now I have a BME 110 mounted and still no balance problems. (Just problems trying to get the engine to run good and not overheat, but that's another story)

Jaketab

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Gentlemen,

Thanks for replies. Now the question remains which engine to go with concerning getting the most power to weight in the 33% Extra 260. DA-85 or 3W-85?

I currently flying a 17lb-2oz WH 300LX with a DA-50. This is the only large plane I have ever flown. To me, it seems to have plenty unlimited verticle power when pulling out of a harrier. I get comments at the airfield all the time what great power the plane has.

What comparison can be made. Will an 85cc in the 33% Extra 260 blow the doors off what I'm currently flying.

Thanks again - Jaketab

rcairflr

My Feedback: (44)

My 3w-80 turned a 26x10 PT models carbon fiber prop at 6050 rpm, when I installed the BME 110 I was getting 6900 rpm on the ground, the BME gave very good power. So if you can get at least 6800 rpm with the 3w-85 or DA-85 on a 26x10 prop, I think you will be very happy with the power to weight ratio. How much power you get out of either engine will also be determined by what exhaust system you use. Choose wisely and you won't have to buy a second engine like I did.

rctom

I'm kind of disappointed in the 3w80, don't know how the 85 will be. I'd go with the DA-85 assuming it becomes available soon.

TF

rcairflr

My Feedback: (44)

Well, I'm glad I am not the only one who feels that way. The engine runs very smooth and has great throttle transition with no mid-range gurgle. Just not enough power.

erikpmort

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what about adding a can for more power?

rcairflr

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The airplane is not setup for a can.

rctom

It does not have a tunnel built in but it can be easily adapted.

TF

Jaketab

My Feedback: (2)

Would the new BME 115 be a better choice for the 33% WH 260 or is that overkill?

Jaketab

rctom

It is overkill but still not a bad idea. If you can afford it the 115 will be spectacular.

TF

imacflyr3

I've got this very combo now......In a word......WOW!!!

If the ultimate power to weight is what you're looking for, this is the combo. I swapped out my zdz80 single for this motor. It balances exactly the same....no weight added or taken out. The ZDZ was on a cannister, the BME is on stock muffs. I flew this in an IMAC contest in Indiana recently in advanced. I had unlimited guys comin up to me commenting on the freakish power! ....one guy even said it accelerated like a foamy!! That upline snap in advanced......no problem....it accelerates out of it like a rocket! I've had to readjust my flying because I'm no longer waiting on the plane to climb through a manuever.

I did have to make an adjustment to the cowl to cover the carb. I made a bubble out of fiberglass and then repainted the cowl. I was planning to repaint it anyway as I patched a large hole that was there for the ZDZ. I'll try to post some pics soon. I also made some glass baffles that wrap around the top of the cylinders.


Gary H.

RTK

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imacflyr3-- I am always looking for new baffle designs, your pics would be appreciated.

krayzc-RCU

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imacflyr3
i am with u i am on the fence to see your pictures.