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New Ds machine.

Started by cambrad, September 11, 2013, 15:37:24 pm

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cambrad

September 11, 2013, 15:37:24 pm Last Edit: September 11, 2013, 16:35:50 pm by cambrad
Finally made a start on my new med/high wind foamy after receiving my foam cores from "Tuckers" ? Really nicely cut and mate together nicely. Cheers!

Intend to go over board with this one, plans include:

4 spars per wing, 2 above and 2 below. ( jw ds special style) 
Removable tip ballast
Central ballast tube
Mks servos with sloperacer bearing kits
Polyurethane nose
Carbon elevons
PU wingtips
Loads of goop anywhere forward of cg
Eagle tree giro

Here is the the the first photo showing the first spar allready installed and the reminder still to fit.



enrico

Certainly going to town with the strengthening Chris  :D

slopeflyer

Nice, Chris, what wing section did you go for?
Going to make a start on a foamy myself, based around an m60, but with uprated bits, and perhaps a little longer span.
Cheers,

deckit

Interesting project, Chris, hope it turns out well :af

Have you considered a wholly joined spar arrangement, triangulated into the approximate shape of a coathanger?
(I'm intending to build a HP60 one day with such an arrangement).

Just a thought.
What covering/s are you contemplating? Heavy NS?
Unless it's going to be as stiff as a good mouldie wing, significant tipweight might encourage the wing to turn to jelly under DS loadings.
I'm convinced both my HP60 & M60 would have suffered this fate at lower speeds had they carried tipweight.

cambrad

Slopeflyer

Dont know the wing section, just seen one fly really well and asked if they could cut me some cores.


Deckit

The problem with this plank is that it needs a heck of a lot of lead up front to balance, so putting a triangular spar systeem in with a lot of it behind cg means it might not be possible to get enough lead up front to counteract to get the cg right.
Same applies to using heavy newstuff, cg probs.

The tipweight ballast tube will be located inbetween both spars and attached to both, so hoping that will stop the "wing tuning to jelly" it will also be removable incase it doesnt work !!
Im trying to decide wether to use a full span ballast tube (carbon fibre) so  i can experiment with ballast slugs and spacers to see the  the effect of spreading the load around.

Like i say this project is just really acting as a testbed for a few ideas, some may not work, some might.

Worth a try :xx

deckit


No doubt tip ballast tubes will be best positioned between the spars, but IMHO that won't prevent a flexible wing giving way earlier when tipweighted up.

But I hope what you learn proves the opposite :af

cambrad

October 02, 2013, 11:29:44 am #6 Last Edit: October 02, 2013, 11:39:52 am by cambrad
Well its almost finished now, a few things i wanted to try out i couldnt for various reasons such as the removable tip ballast which i couldnt make removable due to the sweep of the spars meaning the weight would be too far back to be able to cg ok without tons of lead.

What I have managed to do is :install 4 spars per side (very tight fit !), fit a giro, installed permanent tip ballast of 4oz per side, use high quality servos, pu glued and gooped the epp to the max, made some very stiff carbon elevons and used 250 mill lam film.

As a result of all this, a good amount of lead was needed to balance therefore i am not going to bother with a ballast tube.

Just waiting for a decent forcast now to try it out :xx[attachimg=1]

wdeighton


hobster

Very nice Chris, great colour scheme.
We must be overdue some strong (& dry) southerlies!?

deckit

Look forward to this one at the next big RE blow.
What's the AUW, Chris?

cambrad

Quote from: deckit on October 03, 2013, 00:14:07 am
Look forward to this one at the next big RE blow.
What's the AUW, Chris?


Thanks guys.
Im not sure of the final weight G as i dont own any industrial scales !  ;D