Bidule 170

[gunny11]

Remember guys if you need any CNC cut ply engine spacers, let me know I can help.

Aviation Concepts

[BobM]

Started working on the Bidule this week. I have quite a collection of hardwood and trip stock to use for reinforcing the fuselage. I am also going to use either carbon fiber cloth or fiberglass cloth to reinforce where the elevator/rudders attach to the fuselage in the rear.

Still sorting out the engine mount. I have a local metalworking business that does CNC work looking at my drawings to see if they can make the mount for me. I am also thinking of a simple black of hard maple as another option or ply plates glued with slow setting resin to the correct depth. I also have the round standoffs that can be inserted into the wood plate so there will be less crushing of the wood surfaces.

I made a drawing of the mount, somewhat complex, but it shows what I think would work out of solid aluminum that is then cnc milled properly.



The headers for the DA 170 arrived the other day. I talked with DA about them and they suggested using the KS Comfort Mount Headers, 28mm. These are 11" long as recommended by DA and have 2 portions of the header length that can be bent as needed. This should work to get the proper drop of about 120mm to 130mm for the canisters on the bottom of the fuselage.

I'll work on the fuselage and mount tomorrow and hopefully have some pictures to share tomorrow evening.

[BobM]

I worked on a plywood standoff for the DA 170 yesterday and today. I think this is going to work well.

It is a set of 3 layers of 1/2" aircraft grade ply with an additional layer of 1/4" aircraft grade ply sandwiched between the others.

The layers were cut on the tables to the outside dimension plus about 1/16" extra that is trimmed after glued.

I used West Systems resin for the task and clamped the layers until set. Afterward I trimmed the block and drilled and cleaned up the inner space.

The mount fits the firewall well. From here it will be attached to the firewall with resin and then fully coated with thinned resin to seal it from fuel.

The DA 170 is test mounted to make sure everything fits properly. So far so good.

Tomorrow I start the internal reinforcements on the fuselage with hardwood stock and balsa tri stock.

I should be about ready to start working on the rest of the airframe (tail and wing panels) as well as staring the installation of electronics very soon. Hope to have this one flying in about 2 weeks at the most.

[BobM]

The other photos

[Steve P]

Blurry photo, but first in flight! Len's 170 with a ZDZ180 took to the air today.

Incredibly stable. A beast.

[Swiss1]

Blurry photo, but first in flight! Len's 170 with a ZDZ180 took to the air today.

Incredibly stable. A beast.

And the verdict!

Jeremy and Ben
SCC AAA TT TN

[BobM]

The Bidule is a real winner. Seems to fly great from what I saw as I was being towed. Very powerful and stable.

Len did a fantastic job of getting his together. I was able to get some great insights to things to do on the model to have it ready. Surprisingly not a great deal of additional work or reinforcement, just some basic common sense things like tri stock and hardwood in a couple key areas.

Working on mine this week to have it for Cumberland so we have a couple of them there for the event. My CNC machined engine mount should arrive by Wednesday or Thursday, which is perfect timing as I should have everything but the engine completed by then. Pictures to come in the next few days here.

I found that Revoc makes bags for the Bidule is anyone is interested (found it after seeing what Steve had made for his Arcus).

http://www.shop.revoc.eu/en_US/p/Top-Model-Bidule-170/683

The quality of these wing bags are excellent, very nice to have good covers to protect things. They also have a wide range of covers for many other aircraft if anyone needs some.

Bob

[BobM]

Working away on the Bidule here. I just got an email form the person machining the mount for the DA 170. He had a slip and accidentally left the feed running and cut through the mount in one of the corners. He has been very helpful to work with though and is making the replacement mount and shipping tomorrow.

Here is what it is going to look like (without being milled through though):





The mount should save weight in the nose, which from Len's build looks like a good thing to do (I think Len had to add some weight to the tail for his final balance..

The other thing I really like about this mount is the ability for air to flow around the engine from the rear. Having the metal machined out helps with this, yet the strength is still there with the corner piers being connected to each other.

I still have my plywood mount and I mixed up some resin and thinned it slightly with denatured alcohol. Then I brushed this on all parts to seal the wood. This will be my back up mount should the machined one not arrive before Cumberland:

[BobM]

There are some things I decided to do as far as the build goes with respect to a few changes.

I looked at the hardware and the screws/bolts are all phillips head. I thought it would be better to use hex screws instead. These will be used for the landing gear (nose and main), the tow release block, and also the engine mount.



In talking with Len he showed me how he reinforced the bottom of the fuselage for the canister mounts. One of the things he suggested was to use full ply plates instead of individual reinforcement points.

I made plates that fit inside the fuselage and then put them in place with resin. This should strengthen the attachment of the canisters. I will be using KS Comfort Mount clamps that have silicone tubing on them for the mounting system. There will be 2 rings for each canister to help prevent movement of the canister and reduce the chance the header will break due to stress.

Here are a couple pictures of the fuselage:



The plate just after the wing tube is balsa. I then placed the plywood on top of this in 3 locations:



This picture shows the ply plates and the approximate location along the fuselage where they are eventually installed.

[BobM]

Here is a picture of the plate area where the landing gear plate is attached internally. In addition to adding the ply plate over the balsa I also added 2 hardwood braces to reinforce the attachment of the main gear plate:



These are in front of and behind the gear plate and are on top of ply plates.

The fuselage was also reinforced with balsa tri stock along the inside of the top edge. In addition I also put in 2 hardwood blocks against the firewall to reinforce this:



The blocks have relief holes where the cowl attachment bolts go through to blind nuts on the inside of the fuselage.

The wings and all tail surfaces are set now, hinges are put in place with 5 minute resin. I did decide to replace the hinges with Robart hinge points.I think both Jim Dolly and Len suggested the ones from TopModel are ok, but they do wear and possibly loosen over time.

Tomorrow I do some of the final assembly. Electronics are now installed in several of the final locations. I'll finish that work up so everything is in good order. Then I mount the engine and set the headers and canisters in place.

More tomorrow when I have things closer to being completed.

[lenb]

Excellent progress Bob,
Looking forward to the test flight this weekend.!!!

Len

[BobM]

Hoped to have it ready for some test flights tomorrow, but still working away here. It will be going to Cumberland ready to fly !

Details......details......details.......everything just takes time !

The mount did not make it, hard to tell what is going on with that at this point unfortunately. I used my ply mount (which is heavier than the one being made), but it should work just fine.

The canopy is all set. I decided to pick up some more hardware for the plane.......the hardware is fine that comes with the kit, I just like to use some that is a bit different.

The canopy and cowl are held to the fuselage with 3mm x 20mm phillips head screws. I picked up some 3mm x 20mm button head screws and also have washers that have rubber attached to them to absorb vibration.

I also found some grommets that I will use for the spark plug wires to go through from the fuselage side just behind where the cowl is attached.

I saw Len split his cowl in half, very nicely I must say (his workmanship is incredible !). I figured out from the Bidule manual and pictures included that they just split the cowl from the back side of the engine cylinders to the firewall. A pretty neat trick I think. My thought is to do this also, by also use either fiberglass or a ply plate so the half can be screwed to each other and not have problems.

Other than those changes and ideas I am working away finishing up everything.

I have a Tru-Turn 5" spinner (P-51 style) that should work and I'll be using a Mejzlik 28.5 x 12 3-blade prop as recommended by DA. The canisters are the MTW 110H (a pair them) and using the KS comfort mount rings for holding them in place. DA recommended using the Comfort Mount headers. These have places where they can be bent in 2 different sections so the drop and angle to the canisters can be made to fit. They look pretty good..

Back to work here.......deadlines to meet and hopefully sailplanes to tow in Cumberland !

[lenb]

The weight of the motor mount overall is insignificant in the size of this model.

Love the idea of the cowl, cant wait to see that.
len

[BobM]

Well, after several days last week I had the Bidule finished up and ready for the trip to Cumberland for the Summer Soar.

I arrived Wednesday late afternoon and Len and I got it out and started giving it a try on Thursday.

Like any new plane there were things that needed some attention. These are truly minor, but worth noting:

1) The steering system for the nose wheel does work, but it is important to have a good strong high torque servo for this application

2) The saddle area for the horizontal stabilizer should be reinforced. I used some 3/4" strips of 3/8" plywood to make a couple plates to be in the forward area and then another plate in the back. These were installed with West Systems 105/205 resin and also some microfiber filler to create fillets for strength. The result is a very secure stab now that doesn't twist.

3) The tabs on the canopy for the hold down bolts should be reinforced. This is a simple step of also taking a bit of resin with filler and putting just a bit n each tab inside where they attach to the frame. Also beside the blind nuts are securely glued to the tabs. Some medium CA works well for this.

4) The nose gear has some various metric bolts in place that are not likely set with LockTite. Don't ask me how I found this out I started taking them out one by one and cleaned them with denatured alcohol and applied blue locket liberally. There are 2 in the bottom and then another couple near the top. These should all be checked.

5) The wheels need to have some rolling resistance. The plane tends to roll even at an idle, so keeping the nose wheel tightened as well as the main wheel should help.

Flying this is a dream. It is as easy as a trainer (a very large trainer) and slows down to a crawl with the flaps. Be sure to have a mix with the flaps and elevator for good results.

I am very please with this model. As much as I have had to do some check work on it I think it is a real winner in every respect. It has certainly proven to be an excellent tow plane here in Cumberland the past several days..........Len has been flying his with a ZDZ 180 in it and it just flies great. Mine has the DA170 in it that is new and still getting a few tanks of gas through it yet. Weather permitting here it should get a good workout today.

I'll take several pictures at the field today of the model with close up shots of the notes I mentioned above and add those a bit later today.

[Asher Carmichael]

Bob,
Thanks for the head's up on these issues. I'm sure some will be common with the 111 so I'll check things over as I proceed with my build. Glad to hear you are happy with yours.
Asher