DH Vampire 1/5th Scale prototype - Kit

DH Vampire 1/5th Scale prototype - Kit

Postby DH100 » Sun Sep 16, 2012 1:20 pm

I've been working away for longer than I care to remember with this Vampire project. Time to start to put all things in order and There's been some pretty significant progress in the last little while.

The start was difficult but I didn't realize how much more difficulty there was really going to be. I intended initially to use Kerry Sterner plans. There's a couple of variants flying in NZ and while they fly very well they are not very accurate at all. In fact for the "purists" among us the shocking.

I searched for the best 3 views available, settling on those from Alfred Granger and those supplied with the "Warpaint Vampire" publication. It wasn't until I was way further down the track than I would have liked to have been that good solid info came via the RNZAF Museum Restoration crew. The net result as you will see was a series of modifications to both the prototpye build and later to the mould. One step forward and two backwards in an understatement of massive proportions.

Anyway ..this is how it all started and I hope it will be of interest.
Attachments
117_1701.JPG
117_1701.JPG (111.71 KiB) Viewed 31865 times
117_1746.JPG
117_1746.JPG (55.81 KiB) Viewed 31865 times
DH100
 

Re: DH Vampire 1/5th Scale prototype - Kit

Postby ash » Sun Sep 16, 2012 5:53 pm

Pictures of moulds/moulding would also be of interest at some point if you have any.

What paint system/brand do you use?
Adrian Hamilton > CL + FF

http://ashcustomworks.com
User avatar
ash
 
Posts: 111
Joined: Fri Sep 14, 2012 11:53 am
Location: Auckland

Re: DH Vampire 1/5th Scale prototype - Kit

Postby DH100 » Sun Sep 16, 2012 9:43 pm

Hi Adrian

Yes ... I'll get there. Understand that the model is not yet complete and it's been ...still is a long haul. I'm working to put things in order so it has some continuity. Finding some of my early photographs and remembering exactly what I did is an issue during the early stages.

Brian
DH100
 

Re: DH Vampire 1/5th Scale prototype - Kit

Postby Toast » Mon Sep 17, 2012 8:06 am

Great to see you posting this Brian. I have heard many "stories around the campfire" about this model. Its starting to become legendary! :D

Will be watching with bated breath!

Cheers
Brett
Toast
 

Re: DH Vampire 1/5th Scale prototype - Kit

Postby DH100 » Mon Sep 17, 2012 10:27 am

Hi Brett

The only thing I can say is that the campfire must have beem burning for some long time.

Anyway, to progress a little ..the next issue was to have a mould made. To this end I contacted Alan Ladyman who is a professionl in the Fibre glass business. We talked about the various steps and in the passage of time a mould was produced.

Next a former set was made, some buy computer and some buy trial and fit. I had the basic design set in my head ...now that's a dangerous place... so converting to reality was not so difficult.

Gwyn Avenell then worked his Autocad magic and I now have all these shapes sorted to the point of having Gwyn laser cut future requirements. As with most development projects some changes were inevitable. At least things were going forward.
Attachments
VAMBT3.jpg
VAMBT3.jpg (115 KiB) Viewed 31848 times
DH100
 

Re: DH Vampire 1/5th Scale prototype - Kit

Postby DH100 » Mon Sep 17, 2012 9:24 pm

Ok ...so things don't really move this fast but here's the top moulding.

The mould and mouldings were done by Alan Ladyman. The mouldings are epoxy/glass with a primer sprayed into the mould, hence the grey colour. Being the pro that he is all is very neat with the correct ratios of resin to glass.

The formers and ribs are assembled on a jig and dropped into the bottom half of the mould and the top closed and bolted down. Alan indicated that there was some minor adjusting required which was done of course prior to adhesive being applied to the woodwork for the final fit.

You can see in the previous photograph that the intakes have been located but not the carbon wingtubes. These are captured by the laminated main bulkhead ... the slots for the tube can be seen. There is a Kevlar strapping at the outer ends of the tube to enhance structrural integrity. The loads are carried right across through the fuselage via this former ...exactly like the full size.

Brian
Attachments
VAMBT4.jpg
VAMBT4.jpg (114.99 KiB) Viewed 31836 times
DH100
 

Re: DH Vampire 1/5th Scale prototype - Kit

Postby DH100 » Thu Sep 20, 2012 2:13 pm

Further to the last picture ... I should have said that one of the original booms shows up in the foreground. Sadly the mould had to be binned and a fresh start made. I decided to build the new prototype booms from 0.4mm ply with balsa formers and four stringers. At this point I han't taken a lot of photgraphs so there's not a lot to see regards the actual construction ofthese units.

However, I do have a set of MDF CNC cut boom blanks which were done by Gary Graham. They await my attentions after I've completed this particular model. I've told myself I should have done all the kit work first, but it would have been a nigtmare regards accuracy, so completing my own model first was in fact the sensible direction to follow.

Here's the two units ... the original set has a very slim boom section, is too short and the fin and rudder assembly is too tall!


I'm working with Gwyn Avenell to produce what will be the most accurate set of 3 views of the Vampire available, a result of Serive and Maintainence drawings and measurements from the full size. I'm also writing an article about Kiwi Vampires and colour schemes. There are a couple of surprizes there too!

Brian
Attachments
2012-09-20 14.31.53.jpg
2012-09-20 14.31.53.jpg (235.27 KiB) Viewed 31814 times
DH100
 

Re: DH Vampire 1/5th Scale prototype - Kit

Postby DH100 » Mon Sep 24, 2012 2:13 pm

Having got the fuselage moulded it was cleaned up along the part line which is horizontal. The mould is a little complicated around the intakes but the result is that the intake extensions on the fuselage sides are moulded in place.

The top access hatch to the turbine is a separate moulding as is the removable section of the nose cap …just like the full size. There are cut outs on the fuselage side just below the canopy rails. I will be making use of these spaces one way or another.

At this stage the original booms were partially completed and the method of attaching them finalized. My original intention was to make the booms removable not only from the inboard wing “stubs” but also to make the tailplane removable as well. All this was to ensure a small package for any journey overseas. I have subsequently decided to fix the booms to the tailplane. The disassembled model will be a smallish package anyway.

008.Boom.set.up.jpg
008.Boom.set.up.jpg (51.55 KiB) Viewed 31777 times


Considerations were given to retracts early in the piece. I looked a Sierra units produced for the Sterner Vampire but again I regret that they not up to the mark particularly in terms of geometry. It seemed the only way was to look at producing custom made units with all the “quirks” of the full size. The mains are not particularly challenging but the nose leg is a nightmare. In full size the aircraft is steered with brakes, the nose wheel has a self-centring unit inbuilt. All too difficult in model form, so the nose leg had to be steerable. I made a mock up of the nose leg to check how things would fit and it was going to be very tight in that little snub nose. I now know why people prefer the two-seater!

The attachment 007 Proto Mains.jpg is no longer available


I did however feel I was getting somewhere at this point but the trials and tribulations of developing this model into an accurate, commercially acceptable product seemed to be fraught with difficulty and while not being happy about time spent at least progress was being made.
Attachments
007 Proto Mains.jpg
007 Proto Mains.jpg (44.14 KiB) Viewed 31775 times
DH100
 

Re: DH Vampire 1/5th Scale prototype - Kit

Postby ash » Mon Sep 24, 2012 2:37 pm

That's an extremely attractive leg.
Adrian Hamilton > CL + FF

http://ashcustomworks.com
User avatar
ash
 
Posts: 111
Joined: Fri Sep 14, 2012 11:53 am
Location: Auckland

Re: DH Vampire 1/5th Scale prototype - Kit

Postby DH100 » Wed Sep 26, 2012 3:30 pm

Hi Adrian and all

Version 2 of the retract system is more interesting and the leg itself has yet to be dressed up somewhat. But to press on ....

The full size Vampire features some resemblance to the Mosquito in the way the forward fuselage is built … a ply/balsa/ply laminate. The rear fuselage section is all metal with much of it being removable panels including the entire tail cone assembly. The finish on the front wooden section seems to vary almost from aircraft to aircraft, particularly regards restorations. Obviously some attention was paid to the surface finnish with the application of filler prior to painting as well.

However to cut to the chase ..... given the plywood front was covered with fabric and featured pinked tapes I decided the best idea was to cover the glass moulding with silk. The moulding features some panel lines but not a lot of other surface detail. I found after a couple of test patches that the pinked tapes looked more in realistic when applied prior to covering with silk. (Adhesion was not a problem thanks to the primer being applied to the mould prior to laminating.)

I used Mick Reeves paper tapes, sprayed them lightly with water then coated with full strength dope. They were then laid in place, “squeezed” onto the surface and allowed to dry. Before the silk was applied the tapes were sanded lightly and coated with sanding sealer. The silk was ironed to be crease free then doped on giving a very pleasing result.



I also took the time to indulge in a little more detail …. I like that much more than building and it all has to be done. This is the start of the access panels … you can see the pinked tape as yet uncovered with silk.

Brian
Attachments
006 Access Panel.jpg
006 Access Panel.jpg (40.41 KiB) Viewed 31742 times
DH100
 

Re: DH Vampire 1/5th Scale prototype - Kit

Postby compy260 » Wed Sep 26, 2012 7:58 pm

Looking good. What you planning to power this puppy with?
compy260
 

Re: DH Vampire 1/5th Scale prototype - Kit

Postby DH100 » Thu Sep 27, 2012 2:00 pm

Thanks for that. The powerplant will be Behotec J-66 Turbine. 8.5Kgs Staic at 120,000rpm.... the same engine as is in my trusty old Bullfrog.

History made just a short time ago ...the Mosquito flew out of Ardmore on it's maiden flight.

Brian
DH100
 

Re: DH Vampire 1/5th Scale prototype - Kit

Postby DH100 » Fri Sep 28, 2012 8:24 pm

Some more work on the hatches below the cockpit rails. The locking catches are really too small to make working at 1/5th scale so these will be reproduced with resin castings. The hatch is kept shut with a wire pin accessible from inside the fuselage when the main engine hatch is off. This locates into a brass tube on the inside face of the cover. The back of these doors could be detailed if anyone felt inclined to do so …I drew the line at that given the space may hold the RX, Match boxes etc. They will only be open to get to those items. You can see in these the effect of the silk over pinked tapes here too.

This aircraft doesn’t have huge amounts of detail on the top side apart from panel lines, large removable panels and catches aft of the main bulkhead, fuel cap covers etc but the underside is a different proposition all together. I’ll be getting to that soon enough.

Around now in the build I had real doubts about the back end of the fuselage and in the end I resolved to cut it off so as to have the jet exhaust nozzle align more correctly with the underside of the booms in side view. Documents from the museum in Christchurch showed the correct set up including 1.6 degrees of up thrust on the turbine. I spent some time with my mate Gwyn at the computer trying to make more sense of all the drawings. So that will be next.

Brian
Attachments
011.Hatch.000.jpg
011.Hatch.000.jpg (44.05 KiB) Viewed 14340 times
009.Hatch.jpg
009.Hatch.jpg (40.35 KiB) Viewed 14340 times
DH100
 

Re: DH Vampire 1/5th Scale prototype - Kit

Postby roger.alli » Tue Oct 02, 2012 12:58 pm

Hi Brian,

Thanks for taking the time sharing this build. I will follow it with great interest. It will be a real treat to see exactly how you create the incredible scale detail that you put into your models.

Roger
roger.alli
 
Posts: 7
Joined: Tue Oct 02, 2012 12:38 pm

Re: DH Vampire 1/5th Scale prototype - Kit

Postby DH100 » Tue Oct 02, 2012 8:56 pm

Hi Roger
Thanks for the kind words though there's been so may corrections I'm not sure they're deserved! :roll: However ....

It’s always a tough decision to hack your pride and joy around for a bit of self satisfaction! We all know most models have problems regards accuracy and until perhaps the winner of the last World Champs arrived on the scene with his absolute masterpiece, errors have been something that’s not talked about even though as a designer, a scratch builder or plan and kit builder you may be well aware that in your completed project there are flaws …flaws that we all live with. To some it doesn’t matter too much while to others, perfection is always out of reach.... and it's a curse!

As a result of the Museum documents previously mentioned (and in fairness to Glen Roberts of South Africa who made the point to me some way back) I decided I had to correct what was now driving me mad. I had to cut the tail end off. Making the decision was the hard part. However I also have to modify the mould so every moulding is right rather than wrong.
012 Tail Cone Re-align.jpg
012 Tail Cone Re-align.jpg (41.05 KiB) Viewed 14315 times


So I cut and jigged and packed and sanded. The centre line of the efflux exit was lowered by 7mm and now lines up with official drawings. The top hatch was faired in and the leading edge of that was corrected as well. The frustration level is down somewhat.

013 Tail Cone Blending.jpg
013 Tail Cone Blending.jpg (34.63 KiB) Viewed 14315 times

014 Tailcone and Hatch Blending.jpg
014 Tailcone and Hatch Blending.jpg (119.77 KiB) Viewed 14315 times

A combination of G10, some very light weight epoxy filler and some 0.4mm ply now has the whole thing under control. Being from the old school rather than apply 3/4oz glass to the re-model I covered it with tissue. It's going to sit and mature for a while so I'm sure it'll be fine.

And now on with something else. The tail end sounds like a good idea ...that must be more simple surely.

Brian
DH100
 

Re: DH Vampire 1/5th Scale prototype - Kit

Postby DH100 » Tue Oct 09, 2012 8:28 pm

Hi all
So having made the (new) booms with the new fins and rudders I felt the next task was to make the (new) tailplane and elevator assembly. Once again not too many pics apart from those showing the finishing technique I adopted. I noted on the Motat Museum example that the surface finish on the tailplane is to a lesser standard than that on the wings. While rivets are visible they are not “in your face” so to speak but are still much more obvious that the top surface of the wings. However the construction first.

017.TP.Section.and.detail.jpg
017.TP.Section.and.detail.jpg (36.15 KiB) Viewed 14254 times



The tailplane and elevator feature laser cut ribs located in scale position. The assembly is built as one piece … the elevator is separated later …. on two 6.5mm steel rods to keep it all aligned. It’s a symmetrical section and has a box at each end to pick up the plywood tongues on the booms. It features span wise stringers or skin stiffeners placed at the scale spacing. These are from hard 1.5 x 3.0mm balsa (on edge). These support the light weight covering and help create the scale, slightly “cockled” surface finish.

The tailplane has a carbon rod leading edge and two carbon tube spars on the top surface with hard balsa spars on the lower surface. It features four Robart 3/16 Hinges supported with blocks at appropriate spacing. The elevator has a flat carbon strip trailing edge, a balsa main spar and nose section and also features span wise stringers. The elevator “driver” is located at the left hand (port) end of the unit.

I chose to avoid G10 covering here as I believe it’s weight does not warrant the ease of finish and a quality finish can be achieved in other ways. So, in a quest for a light finish the unit is covered with firm 1.0mm balsa sheet. This in turn is covered with 0.75oz Glass cloth. I chose to coat the glass with a product known as Duratec. This is a specially designed polyester/vinylester high build primer-surfacer designed for the marine industry. It is used for finishing plugs for mould making. It fills beautifully and is very stable when cured but is VERY heavy so only the barest minimum should remain on the surface. Thankfully it sands with ease. One real advantage is that it can be polished to a mirror like surface that is indistinguishable from metal.

15 TP Rivet.Layout.jpg
15 TP Rivet.Layout.jpg (52.89 KiB) Viewed 14254 times


Having got the structure to the above standard I then set about laying out the rivet and panel lines….only one of the latter on both top and bottom surface. (This could be the first part of the model completed ready for painting.)

Low tack masking tape was cut to 3mm widths and placed as required and the unit was given a light coat of regular auto cellulose primer. When touch dry the tape was removed and when completely dry was sanded to achieve the result shown in the photographs. I use both sandpaper and 3M sanding pads and aim for a polished finish …no scratch lines. Next will be the rivets.

16 TP Surface Fininsh.jpg
16 TP Surface Fininsh.jpg (37.55 KiB) Viewed 14254 times


It should be noted that the primer coat over the tape is not heavy in application but it results in a surprising effect after sanding and lightly re-coating prior to the rivet process.
DH100
 

Re: DH Vampire 1/5th Scale prototype - Kit

Postby roger.alli » Wed Oct 10, 2012 12:57 pm

Brian,

Of course you were always going to hack the end of your tail off. The difference between “stand off scale” and Scale!! This is no Bullfrog..

The primer/tape technique for creating panels lines seems very effective. I imaging that you will need to be very mindful with the top coat and clear not to lose the detail.

I am trying to learn as much as I can on finishing metal clad jets, for my Hun project which is slowing moving ahead. There seem to be as many techniques and there are models.

Roger
roger.alli
 
Posts: 7
Joined: Tue Oct 02, 2012 12:38 pm

Re: DH Vampire 1/5th Scale prototype - Kit

Postby DH100 » Wed Oct 10, 2012 7:10 pm

Hi Roger
Yes there are many ways to detail, both old and new. It comes down to a matter of preference and the desired result.... perhaps with a little convenience as well.

I confess for rivets on the Tailplane I was torn between the tube imprint and the perforated tape method and I should have done a test .... but too late now.

Regards loosing the detail, well that's a matter of paint application and in particular the opacity of the paint. You must choose a product that covers really well. I've had most success with Sikkens Base Coat with a clear overcoat. The paint must be well thinned and applied with a minimum amount. Prior to that surface preparation is the key. There's a huge benefit in having a flawless, polished undercoat. You want your model to look like a real aeroplane ... not a poorly painted second hand car!

Also ... a Jet doesn't need a two pack clear coat for proofing. A single pack clear has much greater solvent evaporation than any two pot system.

Keep well ... BB
DH100
 

Re: DH Vampire 1/5th Scale prototype - Kit

Postby DH100 » Sat Oct 20, 2012 12:41 pm

Hi all

My time been spent on other things, like repairing the ¼ Scale Auster AOP9 which I damaged trying to be clever at the last large model meeting. :x At that flying meeting I discovered what I believed to be a damaged gear set in one of the aileron servos. As a result of fire damage to my jet model I was able to replace the faulty servo, carry on flying and thought no more about the issue.

Later at home when I checked the faulty servo I found no gear damage at all. The problem was in fact the servo horn had split around the spline …on both ailerons! They were JR black horns and something tells me I am not the first to discover this nasty surprise. They have now been replaced with standard Heavy Duty JR white nylon jobs.

To Vampires … I set about the rivet detail on the tailplane. This was accomplished with a sharpened brass tube. I spray the surface with thinners, wait a moment, make a number of impressions then move on repeating the exercise. I’m not brave enough to try something rotating in a mini drill.
018 Tailplane surface.jpg
018 Tailplane surface.jpg (86.64 KiB) Viewed 14154 times


019 Tailplane Surface 2.jpg
019 Tailplane Surface 2.jpg (90.03 KiB) Viewed 14154 times

Overall I am pretty pleased with the result. I just can not ignore the detail side and so I progressed the trim tab underside. Next the top side and the mass balances.
021 Trim Tab underside.jpg
021 Trim Tab underside.jpg (94.6 KiB) Viewed 14154 times


Till next time.... Brian
DH100
 

Re: DH Vampire 1/5th Scale prototype - Kit

Postby ash » Sun Oct 21, 2012 9:44 pm

Just amazing, Brian. I find these processes more interesting than the finished product, I think!
Adrian Hamilton > CL + FF

http://ashcustomworks.com
User avatar
ash
 
Posts: 111
Joined: Fri Sep 14, 2012 11:53 am
Location: Auckland

Next

Return to Build Threads

Who is online

Users browsing this forum: No registered users and 1 guest

cron