Fly2XS

My Feedback: (65)

Leonard,
This is an easy look up if you go to the Robart Gear Finder Site and look up under Top Flite:
http://www.robart.com/air-models/f4u-corsair-15-scale-0
Scott

Auburn02

My Feedback: (1)

I was fumbling with fishing the air lines through 1/8" holes I had drilled, but smartly said forget that and ran a long 3/8" bit I had through the leading edge and through the spar to easily feed the tubes through.



So with enough extra line stowed away, I was ready to sheet over the gear mount and wells.





Caked on some filler to smooth out the seams, and I'll hopefully lay down some glass in the next couple of days to move forward with the gear doors.



Side note: is there a "rule of thumb" when it comes to which color Robart air line should extend vs. retract the gear?

Gryper

Hi Cobra

Gryper

I've been reading up a bit on the making of the gear doors on the thread and am going the route of laying up glass over the wheel-well area.The one thing I'm not sure of is how to prevent the fibreglass sticking to the balsa? Any suggestions?

Fly2XS

My Feedback: (65)

That is what Monokote was invented for!
Just iron on a piece larger than the area you plan to glass and you could then prep the Monokote surface with mold release. You then lay up your glass over the prepped Monokote and pop it off when you're done. The Monokote can then bee pealed off.

Gryper

Thanks!I'll look into that!

Auburn02

My Feedback: (1)

All of the methods I've read use Monokote, sheet plastic, or even just packing tape laid down smooth over the balsa. Then spread some vaseline over the film, and lay your glass. This will prevent the glass from sticking to the balsa. Once the resin has cured, pop your mold off the frame and peel off the film.

My biggest problem is going to be marking the door outlines on the glass. I didn't mark them off very well when I sheeted over the wheel wells.

Speedy-Gonzales

My Feedback: (202)

I have tried to contact ROBART concerning I.D. dimensions of their 5" diameter replacement rubber tires and they have not once replied.
Do any of you have a picture of what the internal part of the tire looks like or the diameter of the part of the hub that fits inside the rubber tire?

I may just have to take my hubs to TOLEDO for comparison. I have a set of wheels for a Don Smith Seafury that need some new rubber.

here are some pics of what I have.

rt3232

My Feedback: (6)

Cobra99

To find the wheel wells and the cut out for th strut Hear is what I have done in the past 9How close did you line up the sheeting cut lines to the ribbs ? ) Take measurements from the plan's, and the edges of your sheeting mark corners with a sharpe, Then to make sure you are rite, take a stright pin and carefuly prob for the ribsand edges of spares, once you are sure you have located the cornersput a pin in the corners and then but you plastic covering over them just make sure you iron it down tight to the pins this will leve a little ding in your lay up and will not effect the doors. Then once you cut out the openings you can again varify the corners to get your cut lines.

Iwould also make 2 lay up's of both sides so if you happen to have an accident it will be easyer to recover

Hope this helps

Cheers Bob T

Auburn02

My Feedback: (1)

Thanks Bob. I had already laid down the fiberglass on one side before I saw your reply so I didn't go that route, but I saw what GaryM did on his and it seems easy enough. After the glass cures I'll mark some lines on it that line up with seams in the sheeting, then cut out the balsa (easy enough, just start somewhere in the middle and work my way to the edges), and finally lay the glass sheet back over the now open area, line up the marks and go from there. I'll try to take some pictures of the process.

So I put down my first layup last night. Not sure if it'll be a keeper or not, as this is my first time ever working with glass like this. The first thing I found was that the resin did not soak through like I expected it to, so I had to lay up each layer one at a time, wet it, then lay down the next layer. From some of the step-by-steps I had read, I thought I could just lay down all the layers, pour on the resin, and force it down through the stack. Not so much. Also, the 20 minute Bob Smith resin I have might not be slow enough, as it was starting to thicken towards the end. I kept remixing small batches instead of mixing one big batch up front, but the stuff laid down first was getting tacky while I was pouring on fresh resin. I think the resin is too thick at the surface, but I couldn't drag it to the edges because some of the lower layers were hardening and it was pulling the cloth instead of just the resin. We'll see how it comes out I guess. I wound up only doing 5 layers of 5oz cloth, with 1 layer of 3/4oz cloth on the bottom and another on top. Hope that's thick enough.

I'll attach the pictures this time instead of embedding them.

rt3232

My Feedback: (6)

Cobra99

What I see in the pic's looks good, and it is most likly thick enough 3/32 should be good. especially if you add a pice of lite balsa to sim the inner door structure I have never used the bob smith stuff, my local buddies and I are all using the "west system" as it is vary user frindly


Cheers Bob T

Auburn02

My Feedback: (1)

Ugh, I typed a huge reply and had it wiped out when I hit submit.

I do think I'm going to use the West Systems when it comes time to glass the whole plane - using the pump seems so much nicer than trying to get an equal squeeze from a bottle. Alright, questions:

Which hardener do you use? I'm thinking 206.
How much should be needed to glass the full airplane? Would the small cans (a qt of resin, 1/2 pint of hardener) be enough?
Is there a secret to extending the shelf life if I don't use it all up?

Sorry for the questions, but thanks for any answers! I may try to pick some up this weekend, should be able to find it in local boat stores.

GaryM

My Feedback: (14)

Speedy, hope this helps. This is the Robart 5" tire. The cross section that shows 1.4 is divided into three equal widths, the center raised section that the hub locks into is just less than 1/2 inch. Please overlook the illusion in the second pic that the measurement is not being taken at the edge of the rubber. It just looks that way from being so close to the tire.

rt3232

My Feedback: (6)

Cobra99

When I did my P-47 I just got a std. Kit #105 Resin and # 206 hardner I also picked up a small gram scale from harbor fright and using the little plastic jelly and fruit cups I was able to mix exact vary small batches at exactly the 5 to 1 ratio and you get good working times I tried the tolit paper roll thinngy to pick up the excess risin but did not like the results. So I went with plastic playing cards they are cheep and they work great as squgees to move the material around vary easy to get nice even spreads.

I still have about 20% of my original kit and it seems to be ok now 3 seasons old as I just used a bit to do a patch for a buddy, but I don't let my shop freezehave heat set for 40 deg's

Hope this helps

Cheers Bob T

Corsair brotherhood #5

Auburn02

My Feedback: (1)

Thanks Bob!

Speedy-Gonzales

My Feedback: (202)

Thanks a bunch Gary. My hubs measure 2.780" diameter compared to your 2.724" dimension but I think the rubber tires can stretched .030" per side to fit the Robart tires.

My hubs are wider with a thinner web in the center of the tires but I think I can turn the hubs back on a lathe to fit the Robart rubber.

I got nothing to lose by trying since I believe the wheels came from Gene Barton and Barton no longer sells wheels.

I just think Robart has their wheels/hubs WAY overpriced. I'm going to go ahead and order the replacement Robart rubber and see how it goes.


Thanks once again!

Dennis

Auburn02

My Feedback: (1)

Well I laid up glass on both sides again yesterday, this time with 6 layers of 5 oz glass (between 2 layers of 3/4 oz) and alternating the sheets 45 degrees with each layer. Much better, plus I did a better job with the resin as well. I think these two are keepers. Try to snap some pics in the next day or so and I'll be cutting back into the sheeting to reveal the wheel wells again. Well, I guess before I do that I need to decide if I want to make a spare set...probably not a bad idea in case I screw one up while cutting out the doors. I think I bought the last packs of 5 oz cloth from the lhs though, so I might have to wait unless I can find cloth elsewhere.

Now I need to decide which hinges I'm going to use and how I'll actuate the doors. I'm sure I'll go with something mechanical where the wheels close the doors as the retract, I don't want to complicate things with air valves or servos.

rt3232

My Feedback: (6)

Cobra

I hope you beefed up the wheel well sidesand some blooks inside for atach points of the mechanisim's and if you go to page 1 of the thread there is an index that might help you find ideas, mine work great but they are a little crude.

Good luck and post pic's

Cheers Bob T

stevegauth30

Can I please be added to the list. I am building the Top Flite Corsair 60. Man that wing really looks cool thanks a lot, Steve

stevegauth30

BTW, any advice on re in forcing weak spots or modifications? Any would be appreciated. Thanks again, Steve.

Auburn02

My Feedback: (1)

Let's see if RCU will let me upload pics today. This was the second try at my glass layup, much better than the first a few posts up. Since then I made another pair, so I now have two good pair and one that was practice and is now pretty much scrap.

Tonight I'll clean up the wing (peel off the vaseline coated packing tape) and cut open the wheel wells, and hopefully be able to draw up the outline of the doors on my glass forms. Not sure yet how I'll cut the doors out of the glass, but I know some ideas were posted in here.

rt3232

My Feedback: (6)

Check post # 1 and drop down to Gear doors if you do a quick scan as I remember one of the guys posted a plot with dim's. Sence I had a H/D crash I lost a lot of my info and I do not have any thing in my had notes. as longas you are not going for a lot of detail you can just go wilt square corners.

Cheers Bob T

Auburn02

My Feedback: (1)

Yeah, I've been through the thread and also have the CD that JazzRC compiled with most of the posts/photos from the thread, I just haven't decided which method I'm going with myself yet.

Made some more progress last night, cutting back open the wing to access the wheel wells and gear mounts, and started walling in the wheels wells since I didn't do that before sheeting (I don't know why). Didn't have the guts yet to draw out my doors and cut the glass yet, but once I have a plan it should be pretty straight forward to get them cut to size.

rt3232

My Feedback: (6)

Cobra

Looks good just plan 2 steps ahead so you wont have to back up

Can't tell in the pic's. But did you drop the rails down a bit the thing I learned from my 2 builds was that to get the screw heads under the skin surface I had to drop the rails and then to keep from punching a hole in the upper surface I had to take a bit off from the rod that works the rotation ball and you need the gear right up aganst the leading edge.

Hope this helps you

Cheers Bob T

Auburn02

My Feedback: (1)

I think I did drop the rails down a bit. It's been so long since I glued them in, but I know I read through this entire thread before starting on it and I want to say I did that part.

While I'm still coming to a decision on how to hinge and actuate the gear doors, I may move up front to cutting out the center of the Fiberglass Specialties cowl and fitting the Top Flite mock radial engine.

I'm also not 100% decided on an engine to use in general. I thought I was sold on the G-62, knowing it's very popular for this plane and the weight is needed, but the DLE 55 is still tempting. The goal here being to minimize hacking up the cowl for spark plug clearance and the side carburetor. I can always add weight if weight is needed, but one day (not soon hopefully) when the engine needs to find a new home that airplane may suffer from the extra weight.

Just talking out loud here. [&:]