By continuing to use this site, you agree to our use of cookies. Find out more
Forum sponsored by:
Forum sponsored by Forum sponsored by CML Distribution

Dave Platt P-51 D Build

All Topics | Latest Posts

Search for:  in Thread Title in  
Stefan Hafner21/01/2011 15:02:57
avatar
378 forum posts
15 photos
Having started this build a dew months back i thought I'd put up a few photos and do a wee blog. I've been a bit lazy with photos till now but i'll try to take more
The Plane will be 81" span with a 1.80 four stroke for power and should weigh about 8.5 kg, so should fly nice and slow with the huge wing area that it has
I'm going to bud this particular one i think, as i have lots of photos from seeing it when i was over in the states
so heres the pics so far

The fuselage partly sheeted, and showing the internal ducting that will let the exhaust exit at the back of the plane out the radiator outlet
Another view of the ducting

Fuselage fully sheeted and ready for sanding once the remaining sections have been added to the upper cowl, the lower section is a fibreglass moulding

The tailplane is a simple built up affair so not much to say about it really, here its ready for fibreglassing

Second half of the wing on the jigs, didn't get any pics of the first one on the jigs

The 2 wing halfs laid side by side, i haven't glued the root ribs yet so that i can set the dihedral angle properly
The bottom of the first wing half, with just one side of sheeting on i was surprised how rigid the structure was. Next job is the add some paper tubes to feed all the wiring through and pipes for the retracts, add leading edges and trim down the retract mounts, as i had to modify the the design a bit to work with the retracts i'm using
Stefan Hafner25/01/2011 20:00:39
avatar
378 forum posts
15 photos
BIt more work done today, got the top sheeting on the other wing half done and added leading edges to both half, will get some photos soon
 
Also started work on the canopy mounting, as i want to have a sliding canopy. This means that the canopy frames have to be stronger so i decided to make them out of 3mm aluminium.
 
I started off by masking off the relevant part of the canopy moulding
 

Once the masking was all done, i used a balsa rough guide and filled any gaps between the canopy and template with car body filler to give an exact copy of the shape that i'll need for the frames. The brace behind the template is to keep the canopy at the correct width while the filler sets
 
The finished result after removing it from the canopy and trimming the excess. This was then traced to aluminium sheet ready for cutting out.
 
I couldn't resist a quick slotting together of the parts

Next job is to make the rear canopy frame to add the runners that will fit in the canopy rails
philfly28/01/2011 12:50:29
avatar
25 forum posts
1 photos
Looking very nice stephan im watching. That exhaust duct looks like a major operation is it part of the kit or a mod?
Stefan Hafner28/01/2011 14:28:02
avatar
378 forum posts
15 photos
The duct is part of the design, but i modified it as it would take up a lot od space in the cockpit, so i widened it and made it thinner. As its a "semi" kit you've got the optin not to use it as all the parts have to be cut anyway. I've seen quite a few people make do without it but i like the idea of not having a silencer hanging out the side of the cowl The actual materila is just some fibre glass sheet of the type thats used on roofs
Stefan Hafner30/01/2011 11:06:33
avatar
378 forum posts
15 photos
A few more photos today,
 
First up is the canopy frames that i've now cut from aluminium
They are not quite the same with all the way round from a mistake while cutting them out, so i'll correct that with some plastic and filler at a later stage
 
While doing these i was waiting fro the glue to dry on the wings, which have now been joined and the retract seats shaped to match the wing and to the correct angles

The white tubes are just some rolled up paper, that will make it really easy to feed through all of the servo cables and retract tbes
 
Next up sheeting the wings and cmore work on te canopy frames
Stefan Hafner13/03/2011 11:43:45
avatar
378 forum posts
15 photos
Having had to spend the last few weeks fixing our pump for the irrigation system, the build has been a bit neglected, but some more work has been done now
 
The wing sheeting has been finished and the railing edge blocks and tip added and shaped

I made a slight error in the sheeting at the point where the kink is in the leading edge so i had to fill a small area, this has just been done roughly just now as the filler is a lot harder than the balsa, so i'll get it to the final shape once the wing has been glassed to prevent any low points around it. The photo also shows the flaps and ailerons marked up
 
Next the ailerons were cut free, i did this with a router bit fitted to my dremel and a guide rail held in place with double sided tape to get a nice straight edge, mainly becuase it came with a mini router style adapter, and i wanted to try it out

I just moved the rail over slightly and so i got a nice slot where i will add the aileron leading edge
 

The flaps were cut free as they had to be a tight fit to let me make a replica of the real one, which is hinged on the bottom surface, and has a lip on the upper surface that butts up to the upper surface to give a seamless upper surface

It should look something like this when its all done
Danny Fenton13/03/2011 12:06:55
avatar
6648 forum posts
2649 photos
Hi Stefan looks really good, and is coming along well, I am doing a 69" BT Mustang, though its on the back burner while I finish some other projects.
 
I think you might find the flap is hinged in the centre and the leading edge is radiussed to keep a close fit throughout the travel.
 
 

 
Cheers
Danny

Edited By Danny Fenton on 13/03/2011 12:14:59

Stefan Hafner13/03/2011 14:54:19
avatar
378 forum posts
15 photos
I really can't tell if ithe flaps a re centre or bottom hinged from photos that i've got but as mine are done now theres not really much i can do about it now
 

The hinges will be covered in glass cloth and should blend into the bottom surface

It certainly looks the part when the flps are lowered, now to work out a way to try and completely conceal the pushrods, might just have to sacrifice a little bit of scale accuracy there
Danny Fenton13/03/2011 16:06:40
avatar
6648 forum posts
2649 photos
Hi Stefan, it certainly looks good. You could actuate the flaps from the inboard end with a torque rod, which is hidden by the wing fairing?
 
Found these pics that show the hinging of the flap, but to be honest bottom hinging wont look much different.
 



Cheers
Danny

Stefan Hafner14/03/2011 08:34:16
avatar
378 forum posts
15 photos
I Danny, looks you're right about the centre hinging, but as you say, it doesn't look much different.
 
The flaps are pretty big so I'm thinking i may just use a more conventional pushrod, and as it looks like the flaps have a few hols in the rounded leading edge anyway i can probably hide the pushrod there. I think if I connect the pushrod to the upper surface of the flap and its connected to the servo arm on the side closest to the wings lower surface I should be able to keep it pretty hidden
Danny Fenton14/03/2011 09:38:11
avatar
6648 forum posts
2649 photos
It was good to have to sift through all my data, as I was sure it was centre hinged but didn't actually have evidence. So it has made me look more closely at this area. I think looking at the wing pics it is more lower than centre. Anyway I am sure if it is that hard to figure on the full size yours will be fine.
 
Here is the Taylor version of that area and it is closer to bottom hinge than centre
 
 
 
 

I look forward to seeing yours unfold. I have the fus done, but yet to start on the wing on Taylor version.
 
Cheers
Danny
 
Stefan Hafner15/03/2011 09:01:18
avatar
378 forum posts
15 photos
I did consider the Taylor version, but decided I wanted a bigger version
 
The flaps are almost ready for glassing now
This is the linkage layout that i'm going to use for themhaving the servo arm close to the bottom wing surface will give enough of an angle to avoid having to cut a huge hole in the flap leading edge
This is the pushrod connector, just an M3 ball link held between 2 3mm ply plates. I accidentally baught ball links for model car but these have turned out to be very good, as they are threaded internally on the ball, which means whne its installed there is no play in the link, as i'va had problems with this on a previous model where there was a small amount of play on the bolt, as an M3 bolt is actually 2.9mm dia. and the hols on the ball was 3mm. Doesn't seem like mush but on a big surface its quite noticeable

Here it is installed in the flap, the upper surface of the leading edge will be filled in with scrap and it shouldn't be noticeable when glassed
Stefan Hafner21/03/2011 11:22:01
avatar
378 forum posts
15 photos
More progress has been made, but my camera is flat just now so will get photos up soon,
 
I've added the upper cowl blocks and sanded them to shape, and opened up the radiator outlet/exhaust and have glassed the talplane and sanded it, as i like to get it to a reasonable finish befor i glue it into the fuselage, just makes things easier later.
 
The wing is on hold at the momnent as i'm waiting for a few parts to arrive in the post before i can do the aileron system.
Stefan Hafner06/04/2011 15:16:39
avatar
378 forum posts
15 photos
Got a few more photos of progress, now the camera is alive again
 



The tailplane and fin are now glued in place , U had to put the snakes in before gluing the fin in place as they wont come out again, not my favourite way of doing things but i dont think i've got much choice in the matter. The hold for the rudder linkage is just about visable on the left of the tail end, where the rudder will be connected to give a hidden linkage.
 

This is the linkage for the aileron, as the wings are quite thin at the ailerons I needed a way of hiding the linkage, and after a bit of browsing the web I came across this system as used on the Phillip Avonds Magister, which seems perfect so I thought i'd give it a try, Hopefully i'll get it installed soon so i can see how it works
Stefan Hafner02/06/2011 11:55:54
avatar
378 forum posts
15 photos
After a bit of a break i've now got back to the build.
 
The wings have been glassed, but no photos of that as it doesn't really look much different to before.
 


My least favourite bit of any build, the fairings, added now so don't have to worry about them anymore , They are made from 1.5 mm sheeting and sanded. On the tighter radiuses Ive built up the inside with block balsa, the used car filler to cover that. With the filler there is about 10 minutes where it is half set and goes quite rubbery, which lets it be carved very easilyso it leaves very little sanding to do afterwards. The fuselage has also been blended in to the lower wing surface, with 3mm balsa and filler on the edges.

Also started work on the radiator intake, cut to shape and so far i've added a back wall to it, next is to work out the best way to attach it, as i don't want it permanently attached to the wing, and to open up the front and add some detailing.
Carried on with the rudder area too, the block has now been blended in, the next task is to close up the holes at the back and make the elvatoer match up properly, as the fulelage blends in with them at neutral
Couldn't resist taping on the cowl and getting a photo of progress so far, starting to look like a mustang now
Alan Cantwell02/06/2011 18:01:44
3039 forum posts
is this a Platt one, or a Pica? platt does his own, and he designed the Pica, mine is the Pica one, and is 88",
 
watcha using for up front and tail retracts?
Stefan Hafner02/06/2011 21:25:37
avatar
378 forum posts
15 photos
HI Alan, its the Platt one, slightly smaller at 81" i think. Not quite decided on the engine yet, but thinking along the lines of a 1.80 four stroke of some sort, would love a laser but a bit pricey.
 
For the tailwheel i may have a go at making my own as i may be able to get acces to a lathe and mill, probably much cheaper than buying one, and that way i can make one perfect for the model that will fit easily
Stefan Hafner06/08/2011 19:56:46
avatar
378 forum posts
15 photos
Not been much progress recently. I have glassed the most of the plane nowand its been waiting for sanding but have been busy with other work.
 
I've been doing some work on the tailwheel mechanism and came up with the design below

I had planned on making it from metal, but can't get access to the right machinery, so i'm making it from Carbon Fibre instead. I'll get some photos of progress up soon as I get some good ones taken.
Stefan Hafner17/08/2011 20:13:49
avatar
378 forum posts
15 photos
So heres the latest, I've made a working tailwheel retract



Its mainly made from carbon fibre, and the sides are a carbon balsa sandwich, which is unbelieveably strong for its weight, the whole thing only weighs 27 grams.
 
Next job is to do some sanding of all the fuselage and wing and then get the hatches cut and fitted. Got to clear the bench first for some welding work though
 
Stefan Hafner28/08/2011 11:29:21
avatar
378 forum posts
15 photos
Some more progress yesterday, I've now got the glass sanded on the wings and fuselage, so almost ready for priming and painting. Also been making molds for the tailwheel doors and the heatch i'm going to put in the tail to give me access to the retract. First stage is to prime the area of interest and sand it smooth, first with 400 then 800 grade wet and dry, used wet.

Once that has been given time to dry throughly I wipe off any remaining dust, then add the first mould release agents. The first layer is the add a few layers of mold release wax and polish that till its nice and smooth. Once that's been given half an hour to dry I add a layer ofr PVA mold relese agent, which just acts as another secirity to stop the mold sticking. The PVA release agent shows up as the blue layer in the pic below.
After this has throughly dried the green gel coat is applied, and allwed to partly cure, before adding a layer of mould making putty to add strength to the mould.


The mould making putty is only used on smaller parts, as for bigger parts it would be too expensive to do, and here i've used less than i usually would, as the mould is for a one off part, if it were to be used for a production part I would have made it thicker. After 6 hours setting its separated from the plane and gives a nice mould.
More photos shortly of the actual gear doors and hatch.

All Topics | Latest Posts

Please login to post a reply.

Latest Forum Posts
Support Our Partners
TJD Models
Gliders Distribution
Advertise With Us
PuffinModels
CML
MHS
Airtekhobbies
BMFA
New Poll - do you always stick to your TX maker's Rxs?
Q: New Poll - do you always stick to your TX maker's Rxs?

 Yes, always
 Sometimes
 Rarely
 No, they're too expensive
 No, they dont make what I want

Digital Back Issues

RCM&E Digital Back Issues