Bidule 55 field report

[Dephil]

Having just completed four days of aerotowing in Delaware at the Silent Knights SS GAAT event, I would like to share my experiences flying a TopModel Bidule 55 on tow and in the pits.

The plane came to me second hand and crashed but with a rich-running and very clean DLE 60 flat twin gas engine. Since I received the plane with no nose gear a new one was easily made in my garage and with the capacity for appropriately sized Dubro lighweight wheels. 4-1/2" dia in the nose and 5" main.

In all respects the plane lives up to expectations: the flying is deterministic and stable. Landings are flat and smooth with pronounced ground gradient lift bloom.

The biggest liability the plane has is that it does not fly a 170cc engine as its older siblings, and the diminutive stature in the presence 5M sailplanes and bigger tugs does not engender confidence in the glider line. Many glider pilots (perhaps with cause) turned down a four-five turn tow to wait for the big guns --ZDZ and DA equipped tugs with massive HP-- who could tow the same planes to the cloud base in three legs. Particularly obvious in this group were 1000 hour build planes and super scale planes where the model was too precious to risk an actual scale tow. Makes sense too, yet when confident glider pilots stepped up, so did the '55.

In one instance one of the more dedicated builders took a test tow with a 50 pound 7M ship. The consensus was that the Bidule 55 could get it in the air albeit in a very scale rate of climb, introducing more turns and time on tow--risky but okay in the hands of the plane's own maker/s.

Tow incidence ranged from 20-70 degrees off horizon on ships going from 25 pounds down to nearly weightless. Several 3D type tows were performed as one turn (downwind and upwind leg at release) jobs.

The plane scares pilots because unburdened with a tow it flies fast and my particular plane is set up with tons of surface control authority. The biggest indicator is its ability to flip from knife edge to knife edge fast as one would expect from a true pattern ship. Definitely not a friend building display at a glider field.

The Bidule is the first plane I've owned that was not buil from scratch or a kit. In mounting the hardware for the engine it is clear that the ply quality is marginal and in my repairs I noted a lot of unbonded glue. Factory covering is impeccable and takes removal, replacing, and reshrinking very well.

More to follow.

[Dephil]

I used the Gunny Bumbars method of engine plumbing. I dispensed with an air filter because stupidity sometimes follows expedience. No header TANK, filters on my fill and vent. I use a 32 oz. TDRC fiji bottle style tank with the carb plumbed directly to a rear of tank sipping heavy clug--unknown mfg. it is ver simole to run the carb dry racing into the flight line with this setup. But on engine out an aggressive down line will make it land as though the engine is at idle. I did this in front of several folks and nobody seemed to notice I overtaxed my setup.

The dle seems cheezy: the way the ignition wires fit seems decidedly not positive. Vibration is absurd at idle. Yet it starts easily with the proper incantations.

I have pitts mufflers that appear stock to the engine. Adjusting the phony Walbro carb needles is nigh on impossible with these mufflers fitted. Tony from SKSS figured out how to hammer on the scews from a side angle but with a cowl fitted .. Good luck.

A side effect of the twin with the bottom carb is that the high idle screw blocks the nosewheel control arms. My ground turns are hence limited to approximately 8' radius as opposed to the 120% span/2 that should be expected. It's klugey and lame but it turns.

My servo saver is a 5/8 2024 tube with a die spring fit to the ID mounted in threaded dashpots. The spring theads onto each dashpot and is sleeved by the tube. It is sqishy but entirely adequate.

EDIT: this servo saver is soft at its certerpoint--but it has ZERO play. So when I say squishy, it just means there is no center detent.

Over the course of 4 days of towing and under pressure hasty landings i rebuilt the front strut bogey/caster sideplates once bumping up to 080 half hard aluminum over the 050 I started with. The Losi LST shock was also banded at the threads with interference fit steel rings to keep it from splitting. I added progressively harder springs cut, tempered and ground on the ends to fit the inside of the shock which eventually led to the piston shearing off the chrome rod. I repaired this metric threaded nighmare at the field by drilling a TDRC fuel tank fittint to replace the rod damper and support the spring ang touch down impact loads. It works.

[JimD]

Phil,

You certainly got the test of fire for your initiation into the tow force!

The Bidule 55 with the DLE 60 proved itself to be a very capable tug, I would say amazingly so. Keep up the good work and welcome to the tow dog circuit! 😎

Jim

[Dephil]

The SKSS Great American Aerotow event brings out superb pilots. The tug pilots not only set a high bar for plane reliability and precision flying but also for a high standard of safety abd service. I noted no breakdowns on the flightline and not a single incident on tow due to the tug itself.

I stalled my engine on the flightline three times. The causes are instructive: first while hooking up a tow I allowed my tx to hang and bobble from the neck strap. The kill switch was bumped to the ignition off position. Another time after a long hookup idle i rapidly advanced tbe left stick which killed the engine--leaning the low end fixed this. After that I taxi'd into tall gas and killed the engine. These were part of learning and nobody seemed too annoyed with my having to restart and drag my plane around (dead) by the prop.

[Dephil]

One note on safety: a lot of people who stopped by to chat with me expressed plans to build a gas tug.

it should be stressed you need four ways of killing your engine and the instincts to follow through the sequence in an emergency:

1: kill switch--no radio mixes (especially unknown ones), nothing fancy. One switch must turn off the ignition.
2. Down trim must kill the engine. Set your low end enpoint so you have the idle range you need but so that full down trim goes way beyond killing the engine.
3. Failsafes on throttle and ignition.
4. The wisdom and willingness to prop strike or crash if there is an unsafe scenario.

On the ground the tug pilot needs to ready and willing to get between any safety issue and his prop--even if it's spinning. Have a plan for how to deal with kids, photographers, pilots etc who are on the field. Be ready to lift your tail or tackle your plane if you have to.

The throttle can stick at any time.

[Dephil]

Here are pics of my nosewheel steering servo saver:

[Dephil]

Here are my Nose gear side plates with 30 degree coining. This is 078" 5052 half hard that was laying around the shop--obviously not the right alloy for the job but The gear held up through a lot of ugly landings.

[Dephil]

Bidule 55

[Dephil]

[French1]

We need to have a family reunion with 55/111/170....

[lenb]

Hi Phil.

Nice write up, this should prove very helpful for anyone looking to go this route.
It was a real pleasure meeting and flying with you at this event, I hope and expect to see you on the aerotow circuit now. The Bidule was neat to see and thanks again for letting me pilot the plane around the patch a few times.
A couple kudos to you are due,
1) Anyone can learn to fly a tow plane, but to make a good tow pilot you need to have the ability to listen and take sound advice... You did both of these very well.
2) You didn't give up when things were less than perfect, you spent the night fixing things and came back stronger than ever...

From your "less than perfect" first tow - to your final "excellent tow" this week/end was a good learning experience, you stuck with it and we're proud to have you joining the ranks.

Talk with you soon
LEN

[Csessa]

Phil:,it was great meeting you this weekend. The key here is not so much confidence in the plane. As you said it is difficult to put a prized plane up behind someone you have not flown with before. For my part I thought the first day was a learning experience but by Friday I was comfortable you and the 55. I am reminded like the time that everyone of our great tow pilots had to tow someone the first time. Anyway thanks for the time and effort. We will hookup,again.

[Dephil]

Yeah well it was my first tows ever. I have made my apologies and said my peace privately. I have also tried to be respectful of the work everyone has invested in their planes.

maybe what should be taken away from this thread is: I have time and money in my plane just like everyone else. Some guys didn't want to fly with the new guy, which I have tried to be exceedingly respectful of, yet I flew with strangers perhaps more than anyone at SKSS this week. I never doubted anyone more than the level of 'show me that your radio is turned on and your surfaces move.' I tied on to anyone and everyone and took chances with people I have not seen fly. It's the same thing, just over and over for four days.

Phil

[hello82]

Good to meet you this weekend Phil. and many thanks for the tows! All went great for me with your mini Bidule and I appreciate the work you put in to make it happen, and with the learning curve. I hope to follow in your footsteps too down the road some and learn to tow too.

see ya at another event soon!

Matt

[Dephil]

Power and Radio.

I used a JR XG712 receiver with a RAO2TL diversity antenna in my starboard wing tip. The whips are taped to the underside of the wing in a 90 degree delta pattern. The batteries are A123 2800mah two cells. Everything runs off these pack, including the ignition. There is a JR XPORT DUO powerbox and xbus converter module. This device splits the battery drain over the two packs, hot switches in a battery failure, and has internal power switching. The E-switch is open circuit == power on which is smart. I have no power switches other than this.

I will try to post my idle current draw for this esw setup, but the biggest thing is that there is one 'switch' to mount that controls the whole plane.

Battery drain was 900mah twice a day, on each battery.