Bidule 170 - What we've learned - Build thread, Len

[lenb]

That's wonderful.
Thanks for sharing those photos. It's nice to see the history of the design. Was the 170 developed by them or by Top Models.

Len

[Asete]

The Elusa Club (Michel Bador was the president then) colaborated with the first Topmodel Bidule 116 (MVVS 116 Motor) and the Bidule 58 (MVVS 58) afterwards on that basis Mr. Borde (Topmodel owner and Michel´s friend) got more experience and using the idea of the Midour landing gear (for the nose) together other little things on the fuselage structure improved the model to the now so popular 111 and 55 (DLE Motors).
I have tested both and the real diference is the lack of bouncing with the improved landing gear. The rest depends on the pilot....
Towed with my DA120 powered "111" a 9 meter ASH 26 with 45 kilos a to +1000 meters height.
Not yet see a 170 myself but I guess its more confortable on those situations but most models go in the 1/3 size where a Bidule 111 is enogh.
Answering your question the later Bidule series are Topmodels hard work!

Adrián

[lenb]

Adrian,
I agree with you, the 111 is a powerful and capable tug for sure. I've had the chance to fly and tow with one and there was nothing at the field it would not pull. The 170 on the other hand is a more stable airplane, obviously more powerful and I feel the size makes it easier to see when doing the typical "to the moon" tows we're asked to do here.
You can't go wrong with either one. The small one was a bit small for my taste. It's cute and flys good, but bouncy and affected by wind as typical with planes of that size.


Len

[Dephil]

Len,

In planning for my new Bidule 170, and inspired by your use of the very cool 1000oz*in of torque steering servo (Spek s9020) ... i got out my torque wrench at work and tested the Losi steering bellcrank/servo saver that is at the heart of stew2's Bidule steering upgrade.

i wanted to see how much torque the losi losb2550 would pass before breaking open and how much torque would spool up as the spring compressed.

as a function of turns of spring compression (past the coil nut contacting the spring) here is the torque i measured with half the unit in a vise:

1 turn 35kg*cm max ~500oz*in
3 turn 42kgcm
4 turn 45kgcm
5 turn 50kgcm = 700oz*in

frankly it's difficult to crank it up past 5 turns.

anyway, this was dry: no lube on anything. The servo arm lengths will determine the max torque ths steering servo will see. It will be limited, clearly the device works. But also the friction losses in the linkages i believe will further protect the servo.

this leads to another question: what is the relationship between stall torque on a servo and its ability to take abuse?

[Dephil]

IE the big Spektrum servo will get er done.

My hope was that a lighter servo would do the job but it doesnt really look like it'd be the case. It would come down to non-static forces, like my test, and wear and other factors.

[JimD]

We tried using a 333 oz.in. servo on the nose gear with the servo saver and it just did not have the torque to get the job done...even when the nose wheel was on a smooth surface where turning offered little resistance.Based on our real world experience, the big 1000 oz. in. servo is the best choice.

[lenb]

It's really not just about the Torque, its the size of the gears. These servos have big, heavy duty gears too so its very unlikely they would strip in a jolt situation. After all, they're built for steering.

Thanks for the research on torque.

Len

[Jag]

Hi. It would be great if soembody could provide a part name or part number for the McMaster Carr catches used earlier in this build to hold the wings on. I have never seen these before and it would be great to find out more. Thanks in advance.

[lenb]

I doesn't matter which one you order, you will need to make you're own spacer to set the correct distance from the wing root to the latch.

https://www.mcmaster.com/#catalog/123/2940/=16f745l . scroll to bottom of the page

For technical drawings and 3-D models, click on a part number.

For Mounting Surface Thick.	Material	Latching Distance	Lg.	Wd.	Projection	Stud Head Dia.	Mounting Hardware Included	Mounting Screw Size		Set
0.046"-0.080"	304 Stainless Steel	5/8"	1 3/4"	11/16"	1/2"	3/8"	No	M3	1872A71	$6.12
0.081"-0.128"	304 Stainless Steel	5/8"	1 3/4"	11/16"	1/2"	3/8"	No	M3	1872A72	6.51

Len

[Jag]

HI Len, thank you very much fro the link. I would never have guessed they were called "Slide-Snap Draw latches" in a million years !!

[Gliderhead]

Been following this for some time, Len. Beautiful work.

I suspect the most us glider guys know about tow planes is that they get us into the air. To see what's really involved in a tug is truly amazing, a wonderfully sophisticated piece of flying gear. Though you likely seldom hear it, thank you for your dedication to detail, commitment to a quality build, and most of all for your skill in providing safe tows for us feeble gliderheads.

[Paul Wilco]

Len, I’ve just started putting a Bidule 170, together here in the UK and have a couple of questions that I’d like to ask you. The rear undercarriage has a slight rake on it, which way should this been mounted on the model as its not clear from the instructions ? Secondly, I’m powering the model with a ZDZ 195, which is the same size and weight as the 180. What cans and headers did you use on your Bidule. The headers look solid, did you get then from ZDZ ? Lastly, can you remember the size of your standoffs for the motor to get the correct cowl spacing. Just trying to get some alloy to do the job.

Really enjoyed your build threads which will be of great use to me.

Thanks for your help

[lenb]

HI PAUL.

Congratulations on the Bidule. You'll LOVE that plane.
The gear will have the tapered part to the rear. ( at least thats the way we do it )
The Canister and headers both came from the ZDZ dealer here in the US. The headers are solid and very strong. No flex coupler other thank the teflon coupler. Hard mounted using the rear nipple on the canister and a support up from to help with side to side movement I don't remember exactly, but I think the standoff size was 1 3/8, I will try to confirm that for you.

LEN

[Paul Wilco]

Thanks for the reply Len, really appreciate your help.

[horsefeetky]

thought i would share this i found this dual servo saver for a redcat rampage mt gas truck as well as the steering links very nice 8mm ball links on steering i think this will work well and i also found part number 50201 that has 2 posts to mount the servo savers with. i will only be using one on this build but will keep the other for a rainy day....also redcat has a super hd steering servo for 49.00 on various seller sites that appears to run on 6v as that is the pack used in the truck for rx power. may check it out too.

[Stew2]

Looks like another source of parts! Always good. Keep us posted on how the $49 steering servo holds up. I wouldn't be able to use it as my entire system is on 7.4V, but if it works for anybody running 6V, that will be awesome!! Look like great finds. Bidules Rule!!!

[horsefeetky]

where can i buy the metal servo arm for the 9020 servo.. seems the redcat servo has the same output size..

[horsefeetky]

lenb

clear out your pm in box you cant get any more pm's for now