Tony Nijhuis Vampire Build

[David Brown]

Hi Terry, yes Chris intends to kit the provost by the end of the year but its up to me to get the prototype finished first which has been held up along with other things due to health prob's. I have all the bits to complete it now less tip tanks (plugs are turned and molds at manufacture stage).
Graham I will send mail.

Dave

[David Brown]

Had two more flights with the Vamp at the Catton Garden Party on the Sunday after being egged on by our chairman, I must say I thoroughly enjoyed both of them with some full throttle being used to great effect . I still have not sorted the flaps or brakes so the landings were a bit fast, things to do next month. If any one has any pics from Sunday then please post as I have none of it flying.

Dave

[Dave Parry]

Here you go Dave some shots where I bit to high for my camera so a bit fussy, sorry.

[David Brown]

Thanks Dave

Dave

[Tony Nijhuis 2280]

Dave,

Misplaced your phone number and contact details......can you give a call on 07720 185373. In need to pass on your details to customers needing to buy the 103" Hurricane retracts.....cheers

[chris willis]

Nice one Dave

[Peter Budd]

Nice build, and very useful for me. I have just started one myself, a first from plans. What servos did you use? In particular at the back. I want to sink two slim servos in the fin for a direct connection and am looking at Hitec HS 125MG thin wing. What about the elevator? There is not a lot of room and I want to split the elevator. Can I mix digitals and anologues?

Did you build in both flaps. I was thinking of just doing one as it would be 3 servos per wing otherwise. Do they really make a difference. I never use the flaps on my JL F15.

Cheers Pete

[David Brown]

Hi Pete, forget the split elevator. You have to keep the tail as light as possible and its only a small jet so it does not need it, use the 125mg or simlar like the HS7115 and use a metal horn and servo arm. Rudders I would fix if I did another. I did all flaps but no speed brakes, it lands pretty quick without flaps. There is not much room for ballast up front so keep it light & move the turbine as far forward as you dare without pushing the tanks too far in front of the CofG, also use a small turbine like the wren 54 range, the jetcat 80 is too big & heavy.

enjoy the build
Dave

[Peter Budd]

Thanks for that. The inspiration for this build came from a twin boom scale jet I saw at Elvington in the summer at the LMA show. Not sure what it was.

I have come across a problem that Tony is sorting out for me at the moment. SLEC sent me the wing ribs and UC doublers cut in lite ply and not 3mm birch as it should be. F11 is already in place so am waiting for the replacement before I can do anymore building.

Unfortunately I cant afford a wren. I am with the British Forces in Cyprus and there is a guy here in my club that deals directly with Kingtech and can get me a K80G for less that £1000 so am going with that, but will shift forward as much as I can. They are quite light as turbines go. I have a 140 in an F15.

Excuse my ignorance but which are the flaps and which are the speed brakes on the wing. I may just do one set.

Thanks for the advice on the rudders , I will omit them, that will get rid a lot of turning force at the back.. I might stick with a split elevator as it will give me peace of mind if one servo fails...
Pete

[David Brown]

Yes kingtech's are of simlar size I believe. As for the elevator read the thread on the 16th April (Graham Trever) where one of the servo's failed and it still went in. On the full size they have speed brakes outside the outer flap's which flip to 90 degrees to slow the aircraft in flight not for landing.They can be seen on the attached pic of my 1/5th Sterner Vamp along with the outer split flap next to it and inner flap.

Dave

[Peter Budd]

Will go with a single one then.
What do you think of this. Never heard of them but torque is higher than the Hitec which seems a little low for the elevator on a jet.

http://www.wingswheelsandrotors.co.uk/m ... 3435-p.asp

[David Brown]

Hi Peter there are quite a few out there of that design, I have KST 125MG on stock which are rated at 7Kg on 6V but are 28g against the hitech HS-7115 at 3.9Kg on 7.4V but only 20g. Its only a small elevator and using the servo calculator on the web it only needs around a 2Kg servo for up to 200mph so for me the lighter servo was more important than the power for this project. For peace of mind I would go for the most powerful which fits the needs of voltage & weight. My Vamp has no issues with the hitech HS-125mg I fitted which is only 3.5kg power at 6V or 3Kg at 4.8V and 24g in weight which was the lightest available at the time and its fine, I am using 5V on this plane. Before I started flying Jets I never bothered about servo weights because you had a big lump of an engine up front to help with balance, plus you only need to carry a small fuel load. With Jets its completely the opposite with ballast generally needed to balance plus up to 3 times the fuel load pushing the wing loading up, so the lighter the tail with less ballast works for me.

Dave

[Peter Budd]

Cheers Dave, your advice is invaluable. I have been the same, biggish planes, heavy lumps so servo weights didn't matter.

Can I ask you what radio set up you used, servos elsewhere, receiver etc.. In my F15 I went for a powerbox/spektrum AR9210, dual batteries etc but I am wondering whether there will be space or the need for all of this in this jet. I will use LiFe batteries and a regulator of some sort and would be happier with dual batteries.

[David Brown]

I use Weatronic receivers with JR radio. In the vamp I have a std 10 channel receiver and JR match-box all fed by one 2200mah Lipo through a JR regulator to 5V which has 2 feeds out of it (one to the receiver & one to the match-box) I use the match-box for the 4 flaps so I can adjust each one separately. This in effect gives me two feeds into the system all be it from one battery.Then just one 2200mah for the turbine. On Weatronic you do not use Y leads and I needed 12 outputs for the vamp but only had the 10 channel spare so the match-box fills the need. With other recievers like JR etc you can Y lead flaps, rudder's etc so do away with the match-box. I do not need or use powerbox systems, Weatronic does it all for me. I believe in keeping it simple, your tranny only has one battery so I only fit one on the receiver unless it is over 20Kg. I only use Lipo's now so I can check cell quality & charge quantity into the battery giving me greater confidence in the battery, where as with the nimh batteries I used 2off in the plane because you never new what each cell was doing hence the back up battery.
Since converting to Lipo's this system has to date never let me down and suits my needs.

Dave

[SimonBurch]

Got this plan for Christmas. Has anyone gone with the set up for the rudders as per the plan? It seems they all need some nose weight, I just wondered if the complication of the closed loop on the rudder made much difference?

Going to scratch build mine, so it's not going to be a quick build!

Cheers,
Simon

[Peter Budd]

I didn't bother with rudders and only used one elevator so reduced the number of servos by 3 at the rear. Also the plan has a few minor errors on it so proceed with care. One that springs to mind is the packing under the spar. From above it says 8mm, from the side under the rib it says 16mm. This is the correct one. This is my first from plan and minimal instructions and it has caused me a few problems but none I have so far not been able to solve. Mounting the booms and getting the stab and wing at the right incidence is looking to be the next one.
Good luck
Pete

[SimonBurch]

Thanks for that, I will mark it on the plan. Don't like the idea of not having rudders, will have to have a think about that.

[David Brown]

Hi Simon, the rudders are the main issue, to fix them or not is the question. Mine are on closed loop and apart from take off & landing I never use them so I am thinking if I built another I would fix them. Peter is right in my book reducing the number of servo's in the tail can only help with reducing ballast in the nose. Peter I think my build thread shows how I set up the booms & elevator incidence, any prob's drop me a line.

Dave

[SimonBurch]

David,
Do you still have any pictures of how you did your closed loop set up? I know there is a need to get the weight off the tail, but I can't stand flying models without rudders.....personal preference I guess.

Cheers,
Simon

[David Brown]

I will sort them out for you.
Dave