DH Vampire 1/5th Scale prototype - Kit

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

Postby Warwick » Wed Feb 25, 2015 9:07 pm

My Kerry Sterner 1/4 vampire maiden last week. It flies very well but floats!! Notice I have left out the word scale after following your build.

http://youtu.be/gSr_li-5ADs
Warwick
 
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Re: DH Vampire 1/5th Scale prototype - Kit

Postby DH100 » Mon Mar 02, 2015 2:18 pm

Ah yes Warwick, but like a couple of others I know you have one flying! Well done. So, where is your flying site and what does the model weigh? :D

Nothing dramatic here but jobs that have to be done. I decided to make permanent the fittings for mounting the Hydraulics board. Some time ago I completed the forward locator so the rear hanger straps have been added. There’s a lot of spaghetti to tidy up yet however. I will fit a simple switch to the pump power line allowing it to be electronically isolated when it’s not in use and also to allow control of the bleeding process.
2015.02.28.11.19.29.jpg

Hydraulics.Board.Aft.Mounting.jpg
Attachments
Hydraulics.Board.in.situ.jpg
DH100
 
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Re: DH Vampire 1/5th Scale prototype - Kit

Postby Warwick » Mon Mar 02, 2015 4:46 pm

Thanks Brian,
My Vampire came out at 41lbs dry, a lot of the weight is in the wheels and undercarriage. We fly at a small model runway here in Kuwait.
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Re: DH Vampire 1/5th Scale prototype - Kit

Postby DH100 » Sun Mar 22, 2015 8:52 pm

Finally a layout of the hydraulics I can live with. It seems to have taken forever to reach this point but I now have it tidy and well contained. I have installed a board with the R/C switch, an isolating switch for the turbine and a switch for the Hydraulic system battery. Both the latter two items have a charge facility at the board. There will also be a RX battery charge point there.
Hydraulics.and.switch.board.jpg

I’ve continued to test the hydraulics on a regular basis and I have to say, that apart from requiring to be properly purged of air as a result of my continuous un-plugging a re-fitting of lines, they have worked faultlessly. The biggest issue has been the learn-as- I- go process. It really has taken a lot of time but I don’t imagine for one moment it being as difficult should I tackle it again.
Hydraulic Tubing tidy up Starboard.jpg

Fetso have some nice little plastic retainer clips for 4mm OD tube and this has helped with the tube layout. You can see these nice little blue jobs at the base of the board. I’ve also plumbed the tanks and test fitted that set up and while it all needs a shoe horn it all fits. However, I can’t help thinking that I’m going to have to write a manual for it all!
I’ve also addressed the slop in the nose gear steering and increased the spring size in the compression strut while at the same time limiting the available compression. I’ve reduced the spring compression spec for the mains and increased the available fully compressed travel by around 4mm in order to make it sit more correctly. It actually needs more travel yet, but I can’t do anything about that right now. Oh yes, I’ve done some wood sealing around the engine bay as well. I though it would be prudent with both Jet Fuel and oil for the Hydraulics in the same location.
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Re: DH Vampire 1/5th Scale prototype - Kit

Postby DH100 » Wed Apr 08, 2015 8:37 pm

Time to fit brake lines in order to get the system up and working. I made these some time ago and the 1/16th Brass tube is a little on the large side. I have some 1.0mm OD coming but I’m not sure I can be bothered changing the whole deal. Anyway I set about making the straps to hold the hard piping in place. It was all a bit tricky but they hold well and in fact there is actually one to go in between the two pictured. I just couldn’t wait to try them.
Brake.line.straps.test.fit.jpg

They are made from shim steel, with 1/16th brass tube silver soldered at one end, drilled and threaded to 1.2mm. The other end is simply the shim material turned up as a tag, tinned with silver solder to strengthen then drilled to accept the 1.2mm clamping bolt.
Brake.line.strap.a.jpg

Brake.line.strap.3.jpg

I also modified the nose leg cylinder nipples. There are two different sizes in the picture. I drilled out the existing Robart fitted nipples and press fitted modified Festo Elbows (with 24 hour Araldite).
Modified Cylinder lines in.jpg

I have the 4.0mm OD size fitted to the model and a spare cylinder fitted with 3.0mm OD. I think I’ll mod the mains cylinders as well as I believe the pump is happier with the larger diameter feed lines.
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Re: DH Vampire 1/5th Scale prototype - Kit

Postby DH100 » Mon May 18, 2015 9:49 pm

Things have been a little random here, but I’ve managed to complete the brake line fittings. I took advice offered by John Ranson some time ago and coloured clear tube for the flexible section. I have it all plumbed up complete with pressure gauge. There are some nuts missing for final securing of the doors and the lower pipe junction.
Brake.Pipes.1.jpg

Brake.Pipes.2.jpg


I also have all the flap sections working with a JR Multi Box after some minor re-jigging of the mechanics. So that’s another chore off the list.
Take Off Flap
Flaps.Take.Off.000.jpg

Half Flap
Flaps.Half.000.jpg

Full Flap
Flaps.Full.jpg


Next worry was a tail pipe and no doubt there could be varying opinions about what I’ve done here. Basically, I’ve used the front end of a Mick Reeves Venom pipe as the scale outlet. It comes with a slight “bell” on it, which when trimmed down a little looks much like the tail pipe fitted to Vampires.

Tail Pipe Outer 2.jpg


Tail Pipe Outer 3.jpg


I have no access to a spot welder so I have created 8 stand-offs to locate the inner working pipe using 3mm machine screws with nuts silver soldered on the inside of the scale pipe. Once set to hold the inner pipe they were trimmed off and also silver soldered and flushed off on the outside.

Tail Pipe Test fit 2.jpg


I have a little trimming to do on the fuselage outlet and there will be a small air gap around the outer pipe as well as the extractor gap between the pipes. The extractor gap is aprox. 5.0mm (3/16”) all around. I know this is small(ish) but the main pipe is only 300mm long (12”) and it will be fitted with a large Carbon bellmouth. The inner pipe is 20mm plus short of the short outer scale section .

I will be interested in any comments regards potential problems. I’d like to think it’s pretty much done and dusted.
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Re: DH Vampire 1/5th Scale prototype - Kit

Postby Warwick » Wed May 20, 2015 8:42 pm

Very nice work Brian. Looking forward to the next installment.
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Re: DH Vampire 1/5th Scale prototype - Kit

Postby DH100 » Thu May 21, 2015 11:57 am

Thanks Warwick. I'm creeping closer to the finish line!

I have been concentrating on finalising the wiring…and there seems to be an awful lot…. and now have it as best I can make it, including the set up for the RX Batteries. I’m using “useful nose weight” by way of two 5 Cell 4600mhr Nickle Metal packs with High Voltage Leads to a High Voltage JR 11 Channel RX. I spent a good deal of time reducing all the servo lead lengths with in the fuselage to a minimum. The system will operate with the JR HV11 Channel R/X, a Mulitbox (or Matchbox as some may know it) for the four flaps and another Multibox for the Speed Brakes.

RX Battries 1.jpg


RX Batteries2.jpg


RX Batteries 3.jpg


So the pics here are of the underside of the nose. The Port side carries the hydraulic lines as well as the nose wheel steering servo lead. I have the nose wheel steering mixed to the rudder channel and also to the gear channel so when U/C Up is selected it centres the nose wheel, thus avoiding any mis-alignment in the tight space.
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Re: DH Vampire 1/5th Scale prototype - Kit

Postby DH100 » Sun Jun 14, 2015 4:33 pm

By way of a little light relief I started working again on the nose wheel tyre. I’ve had the basic pattern for some time but it needs detail. I am having the lettering cut from vinyl and looked at a couple of ways to get other moulded detail on. Neil Schrader did a similar thing with a Mosquito tail wheel tyre using a special tool on a tool post in a lathe.
I finally settled on using an ink compass loaded with Tamiya Acrylic paint and applied three or four layers to give an effect.
Nose Wheel Tyre Work in progress 2.jpg

Lettering was done with help from Neil Schrader with some art work and Gwyn Avenell with his vinyl cutter. Some of the letters and numbers needed a little tidying up at this size but it was an excellent base to work with. I added a couple of panels hand cut from regular sticky tape and that’s about how far I’m going at this point. The additional detail is lettering that’s too small to hand cut and I’m not about to spend thousands on a CNC mould! I’ll make a silicon mould and cast a tyre from pigmented Urethane. Then it will be a hub and that will be that.

Vampire NW Tyre detail.jpg



I’ve also allocated a space for the ECU. It will fit snugly on a ply plate above the hydraulics board. The last items are the fuel pump and the solenoids, the filters and the coms cables.
ECU Mounting Plate 2.jpg


The "mood" shot here shows the board tucked up the top and the intakes are at the left and right of the picture indicating just how tight the space is in there.
All pretty boring stuff but very necessary. In spite of it all being a very tight fit accessibility is not too bad. I have been able to trust the set up I’ve had in my previous jet and that was in a tight space as well. Once the system is up and running and proven to be satisfactory I’m hoping there will be little need for pulling things apart too often.
***********************************************************************************
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Re: DH Vampire 1/5th Scale prototype - Kit

Postby Warwick » Wed Jun 17, 2015 4:37 pm

Boring or not Brian I find it facinatiing watching good scale work develop.
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