Spychalla Aircraft

My Feedback: (34)

My friend Pierre and I made a wager. The first to finish and fly a 1/5th scale Wildcat gets dinner for he and his wife on the loser. The airplane has to be a respectable scale machine that is finish painted and basically ready for competition. It has to have a pilot in place but the cockpit does not need to be done. Scale detail including panel lines and rivets are part of the deal. We both intend to fly these machines at the 2005 AMA Nationals in Muncie on August 5th, so that gives us about 6 months to get the job done. My whole family is betting on Pierre; what do they know anyway? Yet I am not intimidated regarding this challenge, so much so that I think it more important for me to finish kit bashing my GWS Corsair into an XF4U prototype (see photo) than to start on that F4F Wildcat. Pierre, on the other hand, has his fuse on the gear and he is mounting his engine as shown below. I hope we are still friends by the time the NATS roll around!

Leo

Ram-bro

My Feedback: (101)

HEY leo, how can we get a piece of this action? Good luck to both of you.

Spychalla Aircraft

My Feedback: (34)

Ram-Bro, This wager is just between Pierre and I. I don't know how anyone else could get in on it. I thought about starting the Wildcat today because Pierre was talking big that he was going to work on his all weekend. Yet I got in the shop and was still more interested in kit bashing that GWS into the XF4U Cosair Prototype. Made some good progress. Moved the cockpit forward with a block of blue foam, made a birdcage canopy plug, and vac formed a nice little canopy. It is beginning to take on the right look.

Leo

Ram-bro

My Feedback: (101)

hey Leo, I was just messing you guys. That is an interesting lil bash .

popierre

My Feedback: (11)

I worked on the gear this weekend, not much done but it's making progress. After talking to Leo and from Doud Imes experience I decided to angle the gear plate back and make it adjustable. This way I will be able to retention the change after the chain settles down and stretches.

Pictures show the cut away made to accept the new plate. I had to make a new aluminum back plate so I could adjust the system by loosing up 6 screws and not having to change the cylinder to gearbox set up.

Pierre

warbird51

My Feedback: (12)

Are these Wildcat's F4F's or might they be FM-2's. A friend has an FM-2 that he restored and it's painted in Atlantic Coast markings (Gray/White paint for VC-13 off the USS Tripoli) I'll have to pass along the pics of the models you are building. Way cool!

Wayne

popierre

My Feedback: (11)

Wayne,

I am building an FM2 based on the N5833, Leo is building and F4F.

Pierre

popierre

My Feedback: (11)

Happy reader here is the next update. I worked on the engine mount, I bought a brand new G62, the problem is that I got the -1 version, for you neophyte out there this means that I got the longer prop hub adapter 1 1/2" long. I found that out when I was going back and forth between the drawing and the plane and the prop was so far out from the cowl. I decided to get rid of the B&B mount and make one out of plywood, This helps bring the engine back a bit and will be better for me to fit that dummy engine coming my way. I heard a lot about people coming back to ma and worry that I will need more nose weight. The fuse is built pretty light in the back compare to the wooden fuse, so I will probably mount the servo as the last step, just to make sure I don't put everything up front and end up with a problem. The engine mount will have everything mounted to it, Ignition, ignition battery and tank; this will be a self contained power plan unit.

Pierre

carlbecker

My Feedback: (3)

I think you will be hard pressed to make it nose heavy. I will make a light tail wheel instead of using Robart's when I start building the next F4F-3.

Keep us posted.

Carl

popierre

My Feedback: (11)

engine mount is now done, I built I so I can remove the whole package and still run the engine if I need to. The throttle servo is mounted just behing the firewhall former, straght shot to the carb , the linkage is only 3.5" long.

I am still waiting for Leo to post something.....

Pierre

Spychalla Aircraft

My Feedback: (34)

Day 1 - It is time to get going on my Wildcat. Pierre is getting too far ahead. I spent the morning making a brass cutter that will allow me to put grooves in square brass. I will be glassing these to the sides of the cockpit. Mounted the gear. The front is going to need a tensioning spring to keep those chains tight. I am working on an idea. The tail wheel from Robart bolts right in. I will have to lengthen the shaft in order to get the control horn for the wheel up into the fuse. Here is how she looks after only a few hours work.

Leo

Spychalla Aircraft

My Feedback: (34)

Day 2 - Built the firewall today and mounted the G-62. The main firewall is 1/2 inch ply. The center block is a 1-1/4 inch stack of ply. All the fasteners are going to be accessed from the back near the gear bay. The engine is offset to the left side by .115" to accomodate for the 1 degree of right thrust that is already built into the fiberglass molding. The engine mount is leveled relative to the wing spar and centered by referencing the sides of the fuse. "NEVER REFERENCE PARTING LINES FROM THE MOLD, THEY ARE NOT CENTER LINES!" (I had one customer that insisted on doing this. It screwed him all up.) I built in 4 cowl mounting tabs that will greatly ease the cowl mounting and I won't end up with any external fasteners visible. Worked on a 2 spring gear chain tensioner. The cylinder is going to be on a slide that will always keep the chains tight. Watch out Pierre! This project is picking up steam!

Leo

popierre

My Feedback: (11)

Ok I finally got the gear to retract, I got the idea looking at Heavy Date dual cylinder, I used the same idea but I kept the same holding cradle my set up is still floating and kept down by the spring. I had some cylinder from a set of gear that got trashed in a crash. Now I get 3 retracts with one large tank of air @ 105 PSI. The air pressure drops by 10 PSI per actuation. I will probably fill up to 110 PSI just before the flight this way I will have 100 PSI in the air. This test was done without the wheels. One think I found out is the gear still wants to stop (slows down a lot) at the low leverage point and this even with the dual cylinders.

Pierre

Ram-bro

My Feedback: (101)

has anyone even contacted Robart to see why they would be selling gear that doesnt work as promised or designed? $700 is a lot of money for a product that is marginal at best.

popierre

My Feedback: (11)

I will be at the Toledo show in April, I know some Robart people so we will discuss the issue, I agree this is a lot of money, I had to work a full week to get this thing to work properly

Popierre

carlbecker

My Feedback: (3)

About these extra cylinders
Guess I'm thinking to much. Using multiple air pistons to retract the gear gets them over the hump and then the gear don't require more than the single cyl. Is it possible to setup the extra cylinders to assist only in 1/2 of the up cycle. Would this give the grunt to move the gear up then stop at some point so the gear do not slap closed and hopefully give that nice slow scale time? Going down with the aid of gravity is no problem and can be slow.

Need more sleep but I'm about finished building the wing on my Claude. I will have to watch out for Wildcats soon.
Carl

popierre

My Feedback: (11)

Hi Carl,

The up action is kind of slow until you pass the slow part or bump after that the gear slam in place[] , I am still playing with the valve adjustment, I am sure there is a way to use two cylinders for the fist 1/2 way up and disable the second cylinder for the next 1/2. This will add a lot of complexity, the best thing might be to use electric motor on a gear box, this will have all the power and the speed can be regulated. I know now that Leo is grinding his teeth, [:'(]electric retracts........grrrrrrrrrr

Pierre

carlbecker

My Feedback: (3)

I was thinking about the attachment arm for the extra cylinders. If it where slotted so that it only provided power in the first 1/2 when retracting. When past the point of greatest load the center cylinder continued pulling while the extra cyl glided along in the slot. Problem is non of this is needed going down. Just a thought for someone to find the best solution to the slow continuous pull up.

Mine works currently with the Dubro at a fast rate. I will see what happens after the Glennis wheels are installed. I don't relish pulling out the drive to modify.

Keep up the updates and pics!!!!

Carl

BigRetracts

My Feedback: (1)

I may be a bit out of my expertise here, but the gear should have never been designed with only one small cylinder. They should have use a larger cylinder to give a more steady retraction rate, or a cylinder with a longer travel and geared down more to provide the force needed. Just my opinion.
Hind site is 20/20 or course.

Darrell

Ram-bro

My Feedback: (101)

Big Retracts, that is part of the problem asI understand it. Robart designed theseto work without the air cylinders. All the engineering is being done by a small grp of guys who spent their money and found that they dont work as advertised and are now re-engineering the retracts to work.

Veltro

My Feedback: (1)

Eurokit (an advertiser on this site) offers an oil operated retract system. It's kinda interesting. It's not hydralocks or air operated. It has its own adjustable electric pump and oil tank. Go to www.eurokit.us and click on "Pro Line Instructions" and then "Oil Kits". It's a pdf file with a schematic.

carlbecker

My Feedback: (3)

I'm not bashing Robart. I tried to make these gear in 1/6 and its not an easy thing to do. I admire those who can make them. Maybe that gave me a little heads up as to what to expect. I'm glad Robart keep the price at $650. I suspect the smaller guys would charge twice this which could take months to get and still possibly have problems and as far as customer service don't hold your breath. I am just looking for a better way for slower retraction. Personally I think air is the way to go. Less potential problems. I had to go through mine and make them loose. I have beat them up a bit and they did suffer through most of my bashing still working. Lots of retracts operate to fast and this is just the challenge to make them better. I would bet the CJ retract better but check out what they look like. Not for me. Its very sad to hear about some of the poor machining, I did not take my drives apart so I don't know what I have.

I'm happy to have them and fly my Wildcat warts and all.

Carl

GlennisAircraft

My Feedback: (1)

Is it possible to setup the extra cylinders to assist only in 1/2 of the up cycle.

Yes, that's not hard to do - use a small button style valve with a "cam" trigger for half of the cycle - once you're halfway, the valve is released, and the second cyl. shuts off.

The drag of the second cylinder might smooth out the rest of the retraction (due to it's drag when not working)

Dennis

popierre

My Feedback: (11)

I did some work on the Wildcat, I somehow got diverted working on a shock flyer. I constructed the stab, I have both elevators done, a lot of sanding and shaping. it will be on the posting tomorrow. I skinned the stab with 1/16" balsa, the instruction calls out 3/32 but I went with the plan. I didn't like to pull the soft balsa over the edge of the trailing edge. I sanded 1/8" down and put some 1/32" ply. more work but stronger and a cleaner edge which looks more like the aluminum skin.

I also didn't really like the hinges, I made some of 0.093" FR4 or Pcb material. I changed it because I like to have strength i pulling on them. This is done with the step. I sandwich epoxied them with a second piece of hard balsa not shown on the pictures.

well it's all for now, getting ready to go to Toledo show.

Pierre

popierre

My Feedback: (11)

OK, I did some work on the Wildcat, I was waiting for Leo to post something, he is now a jet setter traveling around the world while I am working in my basement, I already have some restaurants in mind. back to the bird, I worked on the tail feather and the servo tray. I ran into some problems since I changed the way the elevators are actuated, I had to do some thinking. I also had problems with the tail wheel, the control horn is below the fuse line which I didn't like, I had to make a longer shaft, with this the horn is now hitting the shock absorber.
I had to pull the top fixation back by 3/8".

I would like to know where all the others are on this project, please drop a line.