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

[lenb]

Tonight I finished with the landing gear strengthening. I added the 1/8 Ply cross supports in front and behind the main landing gear plate. They're glued to the side of the gear plate and the fuse sides along with two additional pieces of hardwood tri-stock on the inside of the supports as shown.




Next up was fitting the nose wheel on the firewall and making up the pushrod. I'll be using a Dave Brown carbon fiber pushrod for this application and to make the end fit on the servo side, I ground down the head of a 6mm bold and used JB weld to hold it in.
after gluing it's hung overnight to cure.





Another change that needs to me made regarding the nose wheel strut is the upper attach bolt for the gas strut shock. The bolt that comes installed is fully threaded meaning the strut is pivoting on the threads, which act like teeth and chew up the strut end. To fix this I'm installing a bolt that has smooth shank where the strut rides. The length will have to be cut, but thats not an issue.









My good friend Bob Morrow made some heavy duty steering arms for a few of us last year and it will be used on this Bidule also. The stock arm is weak and will eventually fail, although Jim has been having success by attaching the ball connector to both top and bottom of the arm, therefore applying even action it instead of twisting action when deflected.

[Mosquito]

So you are not using the provided aluminum push rod for the nose wheel steering?

Tim

[Xroadie]

Ahhhh.....now I know! I saw a couple pics in the Cumberland 50th thread of a Bidule that looked liked someone had backed their truck over it Someone must have dropped a "magic acorn" on the end of the runway right before you landed?

Sorry for the loss, but it's nice to have a back-up airframe!! This one will be even better!!!
Pete

[Steve P]

Pete - the acorn became a mighty oak tree and I decorated it with Bidule confetti. An expensive way to celebrate Arbor Day.

[lenb]

Tim,
The pushrod supplied is for their hokey pokey servo protection speculation modification.

No, since the Stewart servo saver does the job, not you need a long straight pushrod as shown above.

Len

[Mosquito]

Makes sense. I didn't really like the one supplied in the kit.
Tim

[Mosquito]

Started today with the Bidule build. We (Kevin and I) started by cutting our own tri stock with Kevin's nifty homemade jig. We now have enough tri stock to last a lifetime!

Next was removing the balsa bottom and reinforcing the firewall area.

Tim

[kjkavaney]

embarrassed with how long it took me to make this first part of the metal servo saver mount...I only wish I lived closer to Tim so we could work together more often...that being the case, we will have to do a lot of our own projects solo to get this bird done. So thankful for all the text and photos everyone has shared on the Bidule 170
kevin

[Mosquito]

looking good buddy!

[kjkavaney]

more today...getting better at this stuff ...been awhile since metal working...
Part two now done...not as nice as Stu's but functional...
next up is fitting all the parts together...
kevin

[lenb]

Looks great Kevin!
A piece at a time.

[lenb]

I'm back...

After a trip down to Miami for the Nascar Finals its time to get back to work on the Bidule.

My computer finally died after 7 years of constant abuse. The drive decided not to answer the call one morning so its time for a new one, unfortunately I may not be able to access the old drive. It's been looked at and they're still not certain. Good news, the new Macbook Pro will have some cool new features once it arrives ( about 3 weeks ) since they're not out yet.

Sorry for the delay.

We left off with the nose wheel being reworked.

We took the two lower bolts out that hold the wheel yoke assembly to the strut. They will loosen up and fall out at the worst time..typically as you're rolling out after a nice landing.


My cure is to drill through the upper bolt hole and up size it to a 10-32 with a lock-nut on the other side. The lower hole was up sized to a 10-32 cap head. Then locktite the crap out of any other bolt on the assembly.



The steering arm is shown here being replace with a much stronger version.




Once interesting finding was how heavy the motor mount standoffs were we used on the first Bidule. Since this is a continued effort to control and reduce the tail weight in this plane, we are weighing just about every component we put up front. We used aluminum blocks to space the motor off the firewall to get the proper length when mounting the ZDZ 180. These blocks are simple and strong, since the ZDZ has a rear mount carb, a box off the firewall is not a great option. When I put the two blocks on the scale I almost fell to the floor--22oz


So----- Rob took them to work and reduced the excess ....

NEW weight----------

wait for it...



wait for it....



10 oz.......

YUP, saved 12 oz in the nose, which means probably 4 oz in the tail to offset them, so a total of 16 oz comes off the plane just by cutting away unnecessary aluminum.

Rejuvenated blocks

[lenb]

While I wait for my motor to come back from ZDZ, we moved on to strengthening the tail a little. It's pretty strong as it is, but over time we found a small crack develop where the Stab LE meets the fuse.

This is the old tail section, you can see the crack right above the tab.



The fix for this is pretty simple and worked well for the life of Bidule 1.
To make it easy to get the patterns needed, I cut the old tail section in half on the bandsaw. It worked great.....



What we're going to do is make an 1/8 A/c Ply filler for part of the bay in front of the stab LE and one for the bay behind the stab LE .. Make them for both sides.




Getting them into the fuse proved to be a problem without proper access. I do not want to cut the side open, so the natural alternative is to cut the bottom open right over the are we intend to strengthen.

[kjkavaney]

After reading about Len's pursuit of reducing up front weight on his motor mounts, Captain Tim sent me back to my workshop to further reduce the weight of the servo saving mounts...
Tim is demanding perfection on his next tow plane... kevin

[Mosquito]

Get back to work Kevin!!!!!

[Stew2]

You can go even further with lightening holes in the forward flange of the servo saver also. Drilling a pattern of 1/2"+ holes in that flange will work fine. If you are going to mount the servo saver further aft in the fuse like Len's new build, then you could also pick new locations for the mounting holes and probably make it easier to mount as well. There are always improvements that can be made, and don't be shy about making them!! Scot

[lenb]

great Kevin, remember, lighter and bigger just fly's better.

[jfrickie]

I was getting ready to pull the trigger and get a Bidule....then I walked out my door this morning and found a pond in my driveway... now instead Ill be running a new main water line instead.
Great watching the build tho.....

[Mosquito]

Jim, were you thinking a 170 or the 111?
Tim

[lenb]

maybe a small float plane instead?

[lenb]

Modifications to the tail are completed.
Ply panels were installed in the rear fuse openings and the stringer installed.



Next up was closing up the bottom, the rear access was filled in with balsa and carefully sanded in to match.



Then the front was applies. Here I used an A/C plywood. I weighed the difference between lite ply and aircraft ply and even though its a 40% heavier, I opted for the extra strength and stiffness in this application. I also added an access hatch for the servo saver and it also is exactly where my canister mounts will attach. This way I can get to the screws with the hatch off.
I'm super pleased with the addition of the hatch.

[lenb]

Before covering the hatch, I pre-drilled all the holes needed for mounting this on the bottom. The two canisters will mount to the hatch, and there will be some vibration too, so I use plenty of screws to attach it. they'll get painted white later.

After covering, make the holes by heating up and AWL with a torch and melting the holes out.