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Wurzel

Started by thermaled, August 06, 2012, 23:46:18 pm

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thermaled

Built the fuselage moulds for this plane a while ago and hoped to sell a few short kits to cover the costs of finishing off my cnc router and going for a fully moulded version.  Wing is rk40   6.5"root  4"tip and 45" span with a straight leading edge,  the theory was to reduce tip stall and seems to work as never tip stalled it yet though it does drop its nose and loose some height if slowed down too much, far happier flying fast even when scratching about. Stab is bolt on t-tail da8000 section with generous tail moment,  elevator servo fits in the tail fin under a hatch  and with a width of around 15mm most small servos will fit in there. Generous fillets under the wing seat gives room to get plenty of tows in there and toughen  up what is a vulnerable area on most planes, however with the taped on wing the plane can survive wing tip strikes on the bottom turn and live to fly again. In really extreme crashes the wing can swing round and give the tail a tickle which can result in some fin and aileron damage but very minor compared to a bolt on wing. Fair to say I have comprehesively crash tested it and still flying the original version after hitting trees, bushes and many tip strikes when hitting turbulence on the bottom turn.
     My version at around 45oz has a 28oz wing loading I think and have fitted a ballast tube to take another 18ozs, it is a bit of a sled and needs a good dive to get some speed going when launching, and will just about gain sufficient height to dive into the circuit in a 15mph wind, but much happier with 20+. Landing is ok, the small part span ailerons slow the plane to a safer landing speed when raised as spoilerons, certainly not a hover landing though. A lighter build would result in an easier to launch and land plane capable of flying in lighter winds, another guy built up the plane from a short kit to 35ozs I think, and very happy with how it flew at that weight. Plenty of room in the fuselage for up to a 4cell lipo, not tried an electric version yet but can see no reason why it would not work great as a lighter build mini hotliner.
   Attached is a few pics but camera is pretty crappy, so will shoot some video tomorrow evening.

Cactus

sweet looking thing, is short kit, fuz and cores, or skinned ready to paint?
how much?
I know you believe you understand what you think i said, but i am not sure you realise that what you think you heard is not what i meant.

deckit

Looks a tough cookie.
Very interested to follow this.

Great to see a tape-on wing. :af

thermaled

Quote from: Cactus on August 07, 2012, 00:23:29 am
sweet looking thing, is short kit, fuz and cores, or skinned ready to paint?
how much?


Short kit
      A short kit consists of epoxy fiberglass fuselage with tail servo hatch cover and turtle deck.  Blue foam cnc cut wing and stab cores.  Fuselage is coloured resin so cloth weave shows through as slightly darker which I quite like the look of. Two pack paint would be ideal and is what most people use but it stinks my house and workshop out making it unusable  and unhealthy in my circumstances, taped on wing lifts off the paint with the tape when painting a bare fuselage so have experimented with pigmented resins to colour the fuselage in the mould. Tapered wet seam layup so good and strong, seams will need a bit of wet sanding to remove last bit of flashing as there is only so much I can do for £75.00.  Stab seat has a ply plate so easy to tap out a thread or fit threaded inserts. Lots of ways to finish the wings, thin ply, carbon, glass, can even substitute the blue foam for epp if using a hot iron on lam film is as technical as you want to get or want a real quick build, Im very flexible and open to options. Also prepared to vac bag the wing and stab with carbon, then cut out and hinge the flying surfaces and fit it all together for an additional £100.00

wdeighton

Quote from: thermaled on August 07, 2012, 02:11:49 am
Short kit
      A short kit consists of epoxy fiberglass fuselage with tail servo hatch cover and turtle deck.  Blue foam cnc cut wing and stab cores.  Fuselage is coloured resin so cloth weave shows through as slightly darker which I quite like the look of. Two pack paint would be ideal and is what most people use but it stinks my house and workshop out making it unusable  and unhealthy in my circumstances, taped on wing lifts off the paint with the tape when painting a bare fuselage so have experimented with pigmented resins to colour the fuselage in the mould. Tapered wet seam layup so good and strong, seams will need a bit of wet sanding to remove last bit of flashing as there is only so much I can do for £75.00.  Stab seat has a ply plate so easy to tap out a thread or fit threaded inserts. Lots of ways to finish the wings, thin ply, carbon, glass, can even substitute the blue foam for epp if using a hot iron on lam film is as technical as you want to get or want a real quick build, Im very flexible and open to options. Also prepared to vac bag the wing and stab with carbon, then cut out and hinge the flying surfaces and fit it all together for an additional £100.00


So £75 For a Short Kit.
And £175 for a Just add radio Kit.

I like the Idea of this plane. I would rather pay  the extra and get the wings finished. Just because it would speed up the build.

I know you are capable of moulded wings, You going to give that a go?

RK40 good choice of section.

Have you seen the discussion on rcgroups in the speeds thread about incidence?
What incidence is this set up for?

what servos go in this beast?

Will

thermaled

Quote from: wdeighton on August 07, 2012, 19:42:44 pm
So £75 For a Short Kit.
And £175 for a Just add radio Kit.

I like the Idea of this plane. I would rather pay  the extra and get the wings finished. Just because it would speed up the build.

I know you are capable of moulded wings, You going to give that a go?

RK40 good choice of section.

Have you seen the discussion on rcgroups in the speeds thread about incidence?
What incidence is this set up for?

what servos go in this beast?

Will


A little more work than fitting gear will be needed, control horns, linkage and servo tray will need to be sourced or made up,  hate fitting gear in planes so consequently am not that great at it, so would rather leave it up to the individual, and would be interested to see how others do their fit out,  also keeps the cost down.

Experimenting with wing moulds at the moment for a different project,  It always looked a messy and complicated way of building wings to me but cant argue with the accuracy and finish, so have finally come round to the idea. Far too much work  and expense to make just for myself though.

Incidence is zero for wing to stab, did try shimming the stab a little to see if it made any differece but went back to zero.

Just about 10mm thickness in the wing for the aileron servos, around 15mm clearance for servo and linkage in the tail.


         Mark


Geoff N

Mmmm tempting, any chance of flaps?
did see a very intresting video about a vaccum infusion method. Upper wing skin placed in the vac bag dry, vac pump pipe at one end and a pipe at the other end of bag going to a bottle of resin. When the vaccum was correct the resin pipe was un clamped the resin was sucked through the layup. No mess :)

thermaled

Can do flaps, yes. Probably  take me an extra 30 min or so, using flaps will move the aileron servos further out on the wing, which will reduce servo thickness to around 8mm without them sticking out. Presume you would want them bottom hinged/ top driven so you would have to route the linkage through the foam core and make up some sort of shroud to cover it up, its a bit messy on a vac bagged wing but possible.  Happy to do anything anyone wants really within reason, but probably best to pm me with regard  to costs or I suspect I will get in trouble with the moderators.

thermaled

August 08, 2012, 22:24:18 pm #8 Last Edit: August 08, 2012, 22:34:51 pm by thermaled
Here is a few vids covering the making of the fuselage mould, they have been around a while but maybe some of you have not seen them, thought I would put them on here as they are relevant and shows the shape of the fuselage better. Web site is gone I am afraid, could not afford to keep it going any longer and did not get much traffic anyway.










wdeighton

Lovely

Made me late for work, But worth it.
did you ever do anything with the poraver?

William

cambrad

Excellent vids, really enjoyed seeing the process of mould making.
Could you make a vid showing a fuzz being made?
Thanks

thermaled

Actually using the last of my poravor to back the top half of a wing mould tonight, got it all boxed off and ready to fill last night. Made the same mistake a lot of people have by relying to much on the poravor with the first half and not using enough fiberglass over the tooling coat, its a bit fragile so doubt it will last very long. Learnt lots though, mainly how not to do things but its all good fun. Top half is going much better, but still lots of room for improvement.

thermaled

Quote from: cambrad on August 09, 2012, 08:50:04 am
Excellent vids, really enjoyed seeing the process of mould making.
Could you make a vid showing a fuzz being made?
Thanks


Sure, will give it a go.

deckit

Thanks!
Fascinating for me, one of the great unwashed.
Great work. More, please.

I'd be very interested in a Wurzel if I hadn't so many planes awaiting build  :''

Hope it becomes a DS stalwart :)

cambrad

Yep, time you got that D60 built G, or are you saving it for the windy season? :ev

deckit

Quote from: cambrad on August 09, 2012, 22:09:01 pm
Yep, time you got that D60 built G, or are you saving it for the windy season? :ev


Yes, it is.
What's a windy season?

wdeighton

I am also very interested. I will order one of these with a moulded (If Available) or layed up wing.
but until I get a couple more projects finished I cant justify another model on the board. must remove digit from bottom and get moving.

Will

wdeighton

Quote from: thermaled on August 07, 2012, 20:51:44 pm
A little more work than fitting gear will be needed, control horns, linkage and servo tray will need to be sourced or made up,  hate fitting gear in planes so consequently am not that great at it, so would rather leave it up to the individual, and would be interested to see how others do their fit out,  also keeps the cost down.

Experimenting with wing moulds at the moment for a different project,  It always looked a messy and complicated way of building wings to me but cant argue with the accuracy and finish, so have finally come round to the idea. Far too much work  and expense to make just for myself though.

Incidence is zero for wing to stab, did try shimming the stab a little to see if it made any differece but went back to zero.

Just about 10mm thickness in the wing for the aileron servos, around 15mm clearance for servo and linkage in the tail.


         Mark


Hello Mark

How the wing moulds coming along.
I still haven't forgotten about this, its still on my list.

thermaled

No much progress Will, maybe next year!

wdeighton

Think its time to place an order.

Any available ready to install?

thermaled

Thanks for the interest Will, unfortunately its a year to late and have lost the desire and finances to pursue my building at present.  Am baffled though, having finally seen a d40 and d60 in the flesh my Wurzel is close to d60 in build strength and was nearly half the price of a d40, same wing section as well, and definately had potential in the right hands to do a decent speed, unfortunately have never been able to afford to go to Wales and get it wound up on some decent sized hills, and would probably have scared myself silly in any case. Cheap, strong and potentially fast, thought I had ticked all the boxed but guess I had to prove it was fast and have never been able to get onto the right hill at the right time. It had an amazing tolerance for slow flying considering its weight, and really lets you know it was unhappy before falling out of the sky and only then would tip stall, due to the straight leading edge wings no doubt,  Perhaps its ugly?

deckit

This plane ticks so many boxes, including its handy size (& we can't get Destinys anymore), great wing section & even a tape-on wing.
Really hope you can recover the enthusiasm to press ahead with the project.
Would orders help?

thermaled

My original post says it all really.  Built the first Wurzel around 2.5yrs ago and wanted to sell a few short kits to fund finishing off my cnc machine, which would enable me to make a moulded stab and wing. Wing would be stretched to 48" as fus was designed with generous tail moment and had this in mind from the begining. Sold 3 short kits at half price to get some feedback, with the understanding they would do build logs post speeds  ect to generate some interest,  2 have never been built and the third went to a guy that lived right next to a good ds hill and was flying regularly, He logged a few speeds and gave me some good feedback so not complaining, but has since stopped flying. Guess I picked the wrong people to help me with r+d in hindsight. I have no spare income to pursue flying and building currently, you guys that are building your own planes know its not the cheap option that it might first appear to be, but have always enjoyed that part of it. I have never been well off, and in pursuit of building moulds and cnc machines needed to generate some sales to pay for materials and consumables, that has never happened  and am where I am.   I still really enjoy building things and learning new skills, dont think that will ever go away, so guess what I am saying is that I am open to offers, if some of you genuinly want a moulded Wurzel how do you suggest I go about it? 
           My idea would be to sell 4-5 short kits which would fund my finishing of the cnc router and making the stab moulds, (small parts to practice and learn on) and also get feedback on the planes before moulding the wings and distributing to the original short kit owners, a plane in instalments I guess, but one in which you get a say on its development as you fly it and direct access to the guy doing the lay ups.  I am a big fan of ply sheeted wings, its simple and cheap, so a good way to go to get those first short kits in the air.  I have been asked in the past how much to vac bag wings ready for servos ect, but it is not a good direction to go in for repeatable quality and accuracy,  and its time consuming, thats my views anyway. This is the direction I went in from the start of this thread, but perhaps I did not explain it very well the first time round!

deckit

Perhaps a way forward is to establish who is prepared to buy & what exactly they want.
Inevitably a price (say, plus or minus 10%) would be required .

On that footing, I'd be interested in a moulded wing & stab version, once available.
Although it'll be used primarily for DS, it would need to be a medium weight build, as I have enough highly-loaded wings already.

But not a short kit, I've too many planes to build.

Also, I do get to DS regularly, so I'd be happy to test - what's happened to the built one apparently no longer flown?

thermaled

Quote from: deckit on August 04, 2013, 16:13:09 pm

Also, I do get to DS regularly, so I'd be happy to test - what's happened to the built one apparently no longer flown?


No idea!  To be honest have not flown my one much this year so far either, ought to build a lighter one for myself as well to get more flying time in. Possible progress on the cnc router is on the horizon, so maybe a moulded Wurzel is around the corner ....fingers crossed.

deckit

Great :af

Look forward to further news.