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Top Flite P51 - 65" span

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Peter Jenkins19/10/2020 18:43:17
1708 forum posts
314 photos

Hi Mike

You don't need to put anything under the elevator as far as I can see when using the hingeing Top Flite use. The tailplane fits into the top of the fuselage and you have to file a slot for the elevator joiner to fit. The front of the joiner is flush up against the tailplane. See the photo on page 36 Item 4 that shows this case.

In my case, as the centre of rotation of the joiner was moved aft by a small amount, I had to file a longer slot in the fuselage to allow free movement. The cover is described on page 36 Item 7. You tack glue this to the elevator, sand to shape and make a slot for the elevator joiner and then separate the fillet from the elevator and glue it to the fuselage to align with the elevators in their horizontal position. In the full size Mustang, as far as I can see, there is no fillet between the elevator and the fuselage so you could, do the same but make sure that there is no fouling of the full elevator with the fuselage.

Hope that makes sense.

Things are not well this side of the pond as we enter the final posturing of Brexit and whether we are going to have a Deal or No Deal. No Deal looks like where we're headed although past experience in doing EU Trade Deals has been that the clock can be stopped to allow a deal to happen at the right time! We are also close to entering a so called Circuit Breaker with the Welsh Government going for this Friday for a 2 week lock down. Covid 19 cases are rising in some parts of the country to dangerously high levels while in the extremities of the nation all seems to be under control! We, like the rest of the world, await a suitable vaccine and effect treatments before we can think beyond the next epidemic!

At least we have model aircraft to build and fly to take our minds off the situation, albeit temporarily!

Mike Mueller 119/10/2020 21:19:00
17 forum posts

Under the rudder and on top of the fuseledge.....there is something that is supposed to be there. Dont see it anywhere on plans. I'd show you a pic, but I .can't seem to figure out how to show pic.....wonders of modern technology..

Peter Jenkins19/10/2020 21:33:46
1708 forum posts
314 photos

Hi Mike, it's difficult to help without a photo. If you follow this link you will find a tutorial within which is another link on how to create an album. https://www.modelflying.co.uk/forums/postings.asp?th=66132

Give it a go as a picture's worth a thousand words.

Peter Jenkins19/10/2020 23:34:55
1708 forum posts
314 photos

Mike

After hunting around I found this photo of the back end of my Mustang.

mustang 170.jpg

Do you mean under the fin as there is nothing under the rudder. The fin glues directly to the top of the tailplane or stabiliser in your parlance. The fin does have a ply dorsal fin part and 2 balsa parts to fair it into the fin and fuselage top decking. The bottom of the fin needs to be sanded/carved to fit the profile of the top of the stabiliser. If you don't the chances are there will be a gap. The leading edge of the fin, that fits through the stabiliser and glues to the former below also needs to be cut to size to allow the fin to sit on top of the stabiliser. Do both carefully to ensure that you don't end up taking too much off.

The above photo also shows the the starboard side of the elevator fairing that is glued to the fuselage and holds the elevator joiner.

Mike Mueller 120/10/2020 15:25:52
17 forum posts

Peter....that small piece below the fin, to the left of the elevator...........above the fuselege......no problem, I just put in a piece..............but I didn't see it on the drawings.............

And then there is the other "old man" issues...........just put together the right elevator.......cut it up, put in the side piece, holes for the elevator, etc........of course, the elevator is shorter than the airleron........and then realized that I had cut up an airleron by mistake...hahaha......so I pieced together pieces onto the airleron, and will have to resize the elevator with the right pieces..........do stuff like this all the time.........

Other "old man" issue...........when I started working on the tail section, I found that it was off center by about 1/2"......everything obviously was off center..........argh.........so I had to cut out a bunch of stuff so I could move the tail section into proper position......used to bother me that I screwed stuff up like that...........not any more..........I have learned how to repair balsa planes, as I seem to crash more than I care to...........so now the tail section is true, and I keep working......it is alot of fun, takes me more time with all the mistakes, but I enjoy it..............

Oh, one more thing..........bought a TF Corsair (84" a bit back........decided that it was too difficult, so sold it, and bought a Hanger9 P51 (89" ARF....wanted something a bit less "challenging......still lots of work to put together, and significantly more expensive to put pieces together.........retracts, servos, and ENGINE.......but looking forward to winter project, and spring flying.......hahaha...

Peter Jenkins21/10/2020 18:38:47
1708 forum posts
314 photos

Hi Mike, I haven't got the plan with me in the house but if you look kn page 36 of the instruction book at steps 7 and 8 and page 37 step 9, it's fully covered there. As I said above, this is odd since the full size does not have any such structure! I suspect its just there on the model to stop the joiner wobbling around before you glue that in place to the 2 elevators.

Good luck with the H9 Mustang. I had an earlier.one with the full set of Robart air retracts and a Saito 200 Ti. Sold the lot to fund my aerobatics!

Mike Mueller 131/10/2020 17:01:07
17 forum posts

Peter. Been doing pretty good here in the colonies.....hahahaaa.....but have come up with a "problem", and wondered what you think. There is always something...............so my wing is a bit off. The right end sits about 1/3/4" lower than the left side..........some of it is that the wing itself is not "level, and I think I can take care of that with some spacers where you connect the wing to the fuselage. My bigger problem is that the wing is "warped' a bit. The right wing in the front is about 1/2" higher than at the root. The left is about 1 1/2" higher. The right wing in the back is about 1 1/4" higher and the left rear is also about 1 1/4" higher than at the root of the wing. . So the rear of the wings look pretty good, and the front of the wings are off about 3/4". If you consider the front and the back should be parallel, then the right wing should be about 3/4" higher, and the Left is about 1/4" too high..........does that make sense? I have the wing completely sheeted, and ready to cover. One more thing.......the left wing is level with the right about a foot out. Then it changes about 1/4" ever 6 inches out to the end of the wing, there it ends up being 1 1/2" more at the wing tip. I'm of the persuasion to just leave it, and work it out flying, adjusting aileron and rudder while flying. Some tell me that I need to steam the wings to being level........don't know how that might work with a wing that is already put together.........I'm not of the persuasion to remove balsa, and redo one of the wings.........what are your thoughts? Be nice now......Thanks!!! Mike Mueller

Peter Jenkins01/11/2020 01:06:26
1708 forum posts
314 photos

Hi Mike

I'm slightly confused by the description of your wing. As designed, the wing is supposed to have a twist in it whereby the ribs twist nose down a little as you move from the root to the tip with the wing upright.

Could you confirm that when you built the wing, you kept the tabs on the wing ribs in place when you pinned the ribs to your building board. As the wing is built upside down, the tabs on the root ribs are much larger than those on the tip rib and that's how the twist is built into the wing. This is called wash out and reduces the incidence of the wing at the tip compared to that at the root. The reason is that as you slow the aircraft down and reach the stalling angle of attack, the root area will stall before the tips do. If the wing is built with a twist the other way, is is called wash in and is to be avoided like the plague. That's because the tips will stall before the root end and there will be a vicious wing drop. Washout is a standard technique on both full size and model aircraft where they are predominantly going to be flown under positive G. You don't find this on fully aerobatic competition aircraft as they spend half their life inverted so an untwisted wing is what you want.

With the wing upright, if you hold you wing on your building board with the root TE touching the board, you would expect to find that the tip TE is sitting off the board. With a 2.5 deg twist, you would expect to have the tip TE about 1.5 inches above the board (Tan2.5 x 32.5). The distance between the LE and the building board should be lower at the tip than at the root but don't worry about measuring that as if the TE measurement is correct it doesn't really matter about the LE measurement unless you've used some very odd ribs!

You should have the same amount of washout or twist on both wings otherwise you will have a built in roll as soon as you get airborne and will need aileron trim to sort out the problem.

You will also have joined the wings together with a set dihedral angle giving a very shallow V. This will also raise the tip of the wing relative to the root. When you join the wings you would have done so with the wings upside down and using 2 bits of balsa planks underneath the centre section to provide the correct joining angle. The wing tips should have the same amount of displacement upwards from level with the wing upright plus the wing section at the tip will be tilted down a bit relative to the root.

I don't know if I've answered your question or misunderstood you. Are you able to put up a photo of your wing? Did you use the same steps as I did when building my wing (see pages 3 and 4 of the build)?

Look forward to hearing from you.

Peter

Peter Jenkins01/11/2020 01:08:38
1708 forum posts
314 photos

By the way Mike, I sent you a PM which you might want to take a look at. It's showing as unread in my Sent Box.

Mike Mueller 104/11/2020 00:45:20
17 forum posts

Peter...not sure I understand the wing fillet installation.......you have anything on that?

Peter Jenkins04/11/2020 18:52:49
1708 forum posts
314 photos

Mike - Ah, wing fillets! Well, I got as far as putting them on and then taking them off as they weren't right first time! That's when the flying took precedence and the Mustang was parked. However, as we have just entered Lockdown 2 in England until at least 2nd Dec, I shall be returning to the Mustang build and tackling the.....wing fillet! Watch this space!

Mike Mueller 105/11/2020 16:37:20
17 forum posts

Peter. Here is an example of how someone has done the wing fillet.. https://www.youtube.com/watch?v=jTvJhEdYE-g

Peter Jenkins05/11/2020 23:51:02
1708 forum posts
314 photos

Hi Mike

Thanks for the link. I did watch it but it seemed to me that he was experimenting in how thick to make his mixture and ended up with it setting before he could finish. I think he has the rear of the fillet wrong as it is too shallow. If you look at a photo of a Mustang the rear fillet is almost twice the size of the fillet at the front and his finished piece wasn't that close to the scale view.

I think I'll stick to the way I was doing it using sheet but make sure this time that the size of sheet I use is wider than before so that it takes up the right contour. I will also be wetting or steaming the sheet before hand to help it to bend to shape, I might use some filler to make good the odd bit but my feeling is that the resin route might end up being heavier.

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