Bidule 111 vs. 170 - larger scale sailplanes?

[BobM]

It may be ugly, but it's effective.........mine was only $99.00 also......go figure !

[Steve P]

Dual Budule, too cool for school.

20170812_140233 by Steve Pasierb, on Flickr


BTW, Since they're 111's, these were two-fer $222

[Steve P]

The dual Bidules are ready for service! A HUGE note of thanks to Len for helping me getting them running smoothly. An additional HUGE note to Bob for his programming prowess.

The 120 was a non issue while the 100 gave us a fight. We never surrender.

Fortunately on the 100, Len had previously experienced a motor where the throttle plate was traveling in the wrong direction and knew how to rework things. We pulled the prop, cowl and carb, did some fiddling and off she went. Bob then took on programming a throttle curve for all three flight modes and we were golden. Here too, Bob had previously experienced a bona fide glitch in the flight modes of the JR 28x software -- every time we dropped the flaps full the motor would die. While we got some nice dead stick landing practice, we finally figured out the full flap induced just a few clicks of down throttle! Programmed that out and we flew the better part of a tank of gas. Fun!

We moved on to the 120 and other than forgetting to eliminate the full flap glitch (Duh! More dead stick landing practice) it was only a matter of adding Expo and taming throws. The 111 on a DA 120 with tuned pipes is a BEAST! I did some tame flying and Len did some hard core aerobatic foolishness and we put it back in the trailer for its trip to Quebec.

I cannot thank Len or Bob enough for all of their time this morning. Thanks too to Jim for the 100 build and to Kris for letting his proven 120 go into new hands.

A great day at Salem.

PS: Stéphane -- Len has my spare 111 wing rod to deliver to you at Winimac. Enjoy.

[Mosquito]

So we don't get to see you at Winamac this year Steve???

Tim

[Steve P]

So we don't get to see you at Winamac this year Steve???

Tim

Sorry, the lure of exotic foreign lands is too strong. A Quebec + Vermont run is our August plan.

All good wishes for a successful event

[rskiba]

So, nearly a year after my initial post, I picked up a complete Bidule this past weekend with all the forum mods already done to it! I am excited and ready for my first aerotow event but first to get some time "solo" flying. Really looking forward to flying this thing!

Question: the plane has a DLE170 in it with a 30x13w Falcon carbon prop. I assume that is the "standard" for the DLE170? Anyone using a tri-blade or something different for other reasons?

[gunny11]

And the best is that it came with brakes too.

[rskiba]

And the best is that it came with brakes too.

The neatest things I have seen on a model plane! I thought air and electric was cool, Gunny's brakes are the ultimate!

[rskiba]

Question: the plane has a DLE170 in it with a 30x13w Falcon carbon prop. I assume that is the "standard" for the DLE170? Anyone using a tri-blade or something different for other reasons?

Didn't want the question to get lost in the shuffle....re-posting.

[JimD]

Of the various Bidule 170 models that I am familiar with, several have DA-150 and DA-170 engines and several have ZDZ-180 engines. I have not seen one powered with a DLE-170 (but that is the engine that TopModel designed the Bidule 170 around).

The main reasons to use a 3-blade prop are either for ground clearance or noise reduction. Prop diameter and pitch also depend on exhaust system...stock mufflers, canister mufflers, or tuned pipes. The guys using the DA-170's and ZDZ-180's are all using 3-blade carbon props. I have built two that use DA-150's.

The DA-150 using either stock mufflers or canisters works really well with a 30x12 Mejzlik 2-Blade carbon prop. Will leave it to others to report their experiences and recommendations for the other engines since I have no first hand experience with them.

[rskiba]

My Bidule has the canisters for the DLE170. Noise reduction would be nice (as I figured) but wondering how much performance hit if any. Should pull more but not as fast right as the 2 blade?

[JimD]

This is an attempt to give a simple explanation to a complex subject.

Basically, a given engine will have an rpm range where it produces the maximum power with greatest efficiency. Prop selection is largely based on allowing the engine to operate at this best rpm range.

Rpm's decrease as diameter and/or pitch increase and vice versa.

DLE recommends a 30x12 or 32x10 prop (2-blade) ... greater pitch gives more speed, less pitch gives better climb.

When using a 3-blade prop (of same pitch as a 2-blade), the diameter must be decreased in order to achieve the same rpm range as the 2-blade of same pitch.

Possible 3-blade choices would be 28.5x12 or 29x12 or 31x10.

3-blade props are typically less efficient than 2-blade props but produce less prop noise. That said, a DLE-170 produces lots of power and a slight loss of efficiency is not going to be a big deal. Also, since the Bidule has relatively small frontal area, the decrease in the prop diameter is not going to be a big deal either.

Hope this helps.

[lenb]

Excellent job Jim, as usual.

I'm not sure what you're trying to two that you need to tweak even more power out of the DA170, but I'd love to know, lol

Seriously though, with the 150 Jim flys on as 2 blade or the ZDZ 180 Scot or myself fly with the three blade props, we've pulled a 90lb sailplane with no issues whatsoever. If sound is an issue, three blade is king, despite the very slight loss in efficiency. You'll finds the loss of efficiency far out weighs the loss of the field.

[Mosquito]

I'm using a DLE 170 on my Bidule with a 28.5x12S Mejzlik 3 blade carbon prop. The down side? $190 a pop! It is quiet and efficient. With the nose gear, I'm not concerned about a prop strike on the ground so the prop should last me a while. "Should" being the magic word.

https://www.desertaircraft.com/products/mejzlik-3-blade-props?variant=1786248257

Tim

[rskiba]

I'm using a DLE 170 on my Bidule with a 28.5x12S Mejzlik 3 blade carbon prop.

Tim

Thanks Tim - that's what I was looking for...

Is the prop drill pattern the same on the DLE as a DA? I have to look as to which drill jigs I have, but I do know they are all DA for now.

--Rob