90mm EDF DB Sport and Scale Vampire

[Reno Racer]

Just had an e-mail reply back from Eddie and Judy Stocker; I'm sure they won't mind me adding details to this website of their newly revamped (no pun intended) Vampire kit for 90mm EDF, electric retracts and flaps. I think its about a 1500mm wingspan, so similar in size to the jet arrows kit, but MUCH better

 

Looks great in the pictures and I'm sure it is fantatsic, if anything like the rest of the DB kits.

 

They reckon the kit should retail at roughly £120. I am definatley buying one and e-mailed Eddie to that effect.

 

Once DB have finalised the kit production and started selling kits I will add a build thread onto here, unless anyone beats me to it!

[Tim Mackey]

Nice...but not sure on the colour

[Reno Racer]

Agreed, I think mine might be silver or camo, that said a nice RN scheme would look quite good.

If I recall Eddie said the AUW is 3Kg, so 6.6Lbs. With glassing/Poly C and paint probably closer to 7Lbs - might have to find some areas to lighten, or go for a 8S Jepe fan set up.

[Dusty]

Looks nice! What retracts will you use Ackers?

[Reno Racer]

Either Spring Air or I might see about electrics. I have some Eflite ones due to be delivered in the next few days and ordered these

I'll probably try both the EFlite and HK ones on a Jepe Fast Foam first. the Lando ones look really good, but also really expensive so I may end up just using good old standard air retracts. I've seen the Fly Fly ones, but I was never impressed by their air retracts to be honest and i can't imagine the electric versions are any better.

I'll wait and get the airframe first, then look at the retract options.

[Reno Racer]

Just had an e-mail from Eddie and Judy, the kit will not be ready until the winter, so a good EDF winter project.

[Eddie Stocker - Formerly, DB Sport and Scale]

Hello all, Well finally it's nearly there. We started cutting our first batch yesterday ready for the re-launch of the new model at end of June beginning of July time 2012.

There is a lot involved with our side of things, but that has (hopefully) made it easier for you guys out there.

Eddie

Edited By Eddie Stocker - DB Sport and Scale on 02/06/2012 12:58:42

[Ruston]

Great news Eddie, I'm sure it'll have been be worth the wait.

Best wishes, John

[Eddie Stocker - Formerly, DB Sport and Scale]

I should say that since the first posting (starting this thread) our guestimated release price was a tad out, but that was a year ago and no accurate materials costing or production time had been properly calculated.

Now that is done, the price is as per our website, I won't post the web address here as it may infringe the terms and conditions or code of conduct on this site, and I wouldn't want to do that.

You know where to find us,

Eddie.

[Ruston]

Hi Eddie

Just a quick question, do you know the bare airframe weight (less electrics and fan unit)? I am hoping to get away with a 9s setup which, using one of these fan units, should give about 2500W **LINK**

Otherwise I'll need to get a load of new batteries .

Thanks, John

[Eddie Stocker - Formerly, DB Sport and Scale]

Hello John,

The bare shell weight (no servo's, no covering, no retracts, in short, just the wooden structure) comes out to about 1.5Kg. That fan unit looks the biz, and especially with that amount of static thrust.

Eddie

[Reno Racer]

Eddie, That sound great, lots of opportunities to keep it light for a less expensive EDF set up, keeping it to about 8Lbs should be fairly easy.

I too am a fan of Jepe's fans. Not sure what magic he does, but his fans kick out a lot of thrust for not alot of Watts, henec Amps. In fact, If I recall from my notes, the 6S Jepe fan kicks out 6.6Lbs of thrust for just over 1200 watts and 54A, that's as my thrust as a Medussa Motor on a Midi Fan on 7S, but with less Amps.

[Ruston]

I'm wondering if 6s might be an option on this plane. The new version of the 6s Jepe fan gives 3kgf at 1500Watts **LINK** I reckon an all up weight of around 3.6kg to 3.8 kg (circa 8lbs) could be achieved:

Bare airframe 1.5kg

Covering, detailing, finishing etc 300g

4000mAh 40C 6s 720g

Jepe 6s fan unit and motor 330g

110A ESC 90g

Seperate 5A SBEC 30g

6 full size servos 270g

Reciever 15g

Eflite 46 size retracts 260g

Struts and Wheels 200g

Perhaps I'm being optimistic with some of these weight estimates but circa 200Watts per lbs and 80% thrust to weight should be enough for a scale like performance? What do you guys think?

Edited By Ruston on 09/06/2012 15:25:37

[Reno Racer]

Might be marginal and require almost full throttle all the time, but hopefully it should work- be great if it does so that the price can be kept down.

PolyC and very lightweight, almost silk like glass fibre and good use of carbon fibre to strengthen might keep the weight down, especially if you can lighten the airframe some more.

I think the 8S fan might be better.

Just thinking aloud - on a 6S set up, might be better to just bungie launch and get rid of the undercarriage (like the Aeronaut version).

[Eddie Stocker - Formerly, DB Sport and Scale]

Psst,

Just a nod Miron (the designer) bust his undercart on a grass strip landing, so he folded the undercarriage away feeling a bit dejected. He then decided to do a couple of fan run ups for testing purposes (this was in the very early days of the prototype flight tests) and the Vampire went hurtling along the grass strip, so he decided to give it the full gun and up she went.

Since then, he has very rarely used the U/C, only when taking of & landing on tarmac. The only down side to that is that the flaps need to be tucked back up just prior to touchdown, or the servos suffer.

The profilm covering underneath shows very little sign of scuffing after about 50 such operations, and that is all with a 5KG AUW.

Eddie.

[Reno Racer]

Eddie,

I can't quite see from the build photos on your website, how is the air inlet ducted to the fan?

I presummed via the inakes at the wing root as normal, but there seems to be a fair few formers in the way for a good clear smooth air flow to the mouth of the fan. Is to be there a GRP ducting or similar thats added to optimise EDF efficiency?

Thanks

Chris

[Reno Racer]

Just checked the T/W ratio of the Vampire FB5 with DH Goblin which generated 3350lbs of static thrust for an airframe AUW of 11000lbs, so T/W was only 0.3, so maybe if the airframe is fairy scale, then a 6S EDF set up might work. I note on the video on Eddie's site that the take off was fairly quick and landing actually quite slow with those flaps, so a lighter 6S set up might be worth a go.

Of course the other option (harking back to DF days) would be to use a take off dolly.

[Eddie Stocker - Formerly, DB Sport and Scale]

Hi Chris,

There is a very good deal of airflow via the wing root intakes (for a turbine) but for the EDF additional material is needed to be removed extending forward of the normal intakes (see the very top one of our web pics). it can also get more breath via the nosewheel opening.

There are no pre-formed GRP airflow parts in the intakes, that's the beauty of building, these kind of things are formed if required from balsa by the builder, there's ample room to do it.

Eddie

[Ruston]

Another option for the fan unit are these alloy 12 blade fans that Hobbyking have just started stocking **LINK**. They are EPF Hobby fans that can be bought elsewhere but are cheaper from Hobbyking. I managed to order a 8s version before they ran out is stock, within 6 hours of them going live on the site! There is also a 6s version. Not quite as efficient as the Jepe fans looking at the numbers, but they sound amazing: **LINK**

[jez]

I have just started a build on this kit , and am looking for retracts , any sugestions would be welcome I have thought of using e flight electric , but the mounting is a bit narrow for the bearers on the plane , also the nose one sticks out of the fuz too far suggestions please

jez

[Klaus Ehlers]

Hi Jez,

i had some headaches wit the undercarriage as well.

In the end i choosed a pneumatic Behotec C21 set with a Behotec 90mm trailing frontleg using a 60mm diameter light wheel a and 110mm Jet 1A trailing legs for the main legs. Combined with the 95 mm "scale wheels" of DB Sports this setup is reasonable and lightweight. The mainwheels are flush with the wing surface, but not the legs. I intend to build an alumina litho sheet cover.

For the Behotec retracts the vampire bearer strips are too wide, therefore i filled the gaps with beech plywood parts.

For the frontleg the retract had to be mounted on the level of the balsa topside of the mounting bearers instead of the bottom. It was necessary to replace the balsa by plywood and glue in some reinforcements as well.

The retract equipment i bought at www.jautsch.de

Could You tell me about the edf setup You'll use?

Mine is an ejets 90 V2 with an 8s lipo ,Casle ICE 1020 HV controller and a HET 70-68 1680 KV motor.

The first measurement at full throttle today showed just 2,52kg thrust, only. Here is something to do- maybe some cheater holes will help.

Klaus

[jez]

hi klaus

sorry for slow reply ,

i have now used rob art air spring retracts and oleos and have struggled with it but got them in finally !

thanks for info , i am also using a het 70 -68 1680 kv motor on a jet fan 90 mm .running 8 cell

not got an esc yet !

just sheeting the wings etc and not shure that the air intakes are big enough ? but as per plan , i have cut out the extra holes in the side of the fuz as the instructions say , what are your thoughts ?? great build though really enjoying it will put some pics on my albums asap

regards jerry

Edited By jez on 11/01/2014 22:38:29

[Klaus Ehlers]

Hi Jez,

fine to hear from You! Maybe we are the only ones worldwide building this vampire.

The air intakes are really too small, even with the cut outs at the fuselage sides. With closed hatch i just reached 2,5 kg thrust. With removed hatch 3,7 kg. So i decided to add some cheater holes to the fuselage bottom. I removed the balsa planking between former 110 and 112 and replaced it by a sheet of 1,5 mm plywood, containing 250 drilled 6mm holes.( Maybe a stamped alumina sheet will do the same job easier). The fotos show the holes closed by a japico paper covering for to apply some filler to fix some unevenesses. This brought a trust of 3,2 kg's , enough for my unvarnished Vampire with a weight of 4,2 kg. The finished plane should reach a thrust/weight balance of > 0,7, that must be sufficient. Not to forget: An edf inlet ring is a must, and the fuselage outlet for the edf should be as wide as possuble. Mine has a diameter of 65 mm.

My esc is a Castle Edge 120 HV. The ground test of the Vampire brought a max suction of 121 amps and 82°C esc temperature after 4 minutes. The advantage of the Castle esc is the casle link system for programming the esc by a PC, and the included data logging. If You are interested in some graphs, please let me know.

I decided to make the boom rudders functional. Therefore i mounted a slim servo in one boom head (there is space enough). The rudders are coupled by a 2 mm glassfiber rod.

I think the pictures at my album explain it all. I'm waiting for springtime temperatures to sprayfinish the Vampire (autdoor).

regards

Klaus

[jez]

hi klaus

thanks for the info i will keep you informed as my progress , i like the pictures , she coming on well what colour scheme are you thinking off i, the guys in my club are all saying silver ,

i think some extra holes will be fitted to mine ! , i am looking at using 8 cell lips but might try 6 cell to start with and test the performance ?

that esc seems to be the one to get , bit pricy but worth it

regards jerry

[Klaus Ehlers]

Hi Jez,

i choosed the colourscheme of the very first Vampire F Mk.1 of the 247 squadron odiham 1946.

Humbrol has the BS resp. FS colours dark green, ocean grey , medium sea greyof (post-) WW2 besides the "sky" marking that is available under Revell no. 32159.

regards

Klaus