Bad Driver

Hi Guys,

Besides the Panic bipe I mentioned previously - which is proceeding slowly (as ever with me ) - my other current project is the Sirex Super Wasp.

This design calls for a fuse made of 2 off 3/16" x 4" x 48" long balsa sheets laminated onto glass-cloth for strength. Unfortunately 48" long sheet is very rare in the U.K. so I was wondering if anyone had any advice on lengthening a 36" piece ? I was thinking that that a diagonal splice (as long as possible) would be best with this joint 'under' the 1/8" ply nose doublers. I can't think of anywhere else on the fuse where this join wouldn't be a weak spot

Also while I'm on the subject would Carbon Fibre cloth/tape be an improvement over the 4oz glass-cloth ? Could I use a lighter CF cloth for the same rigidity ?

If you guyz didn't give such greta answers and replies I wouldn't ask so many dumb questions

Thanks very much as always !

Bad Driver.

P.S. A little early I know, but Happy 4th July to ya !

PaulSwany

My Feedback: (45)

You can use a "Z" cut in the balsa to fabricate a longer piece... Although it might prove to be a weak spot in your design.... I've built 2 wasps... If I had to do it over again... I'd increase the fuse area a bunch... I'd add 2" to the bottom and 2" to the top... And use a stick built up design with 3/8 sticks in the center and sheet with 1/16"... Or better yet... You could build the wing with a pocket and use a CF tube assembly.... You could probably even talk me into drawing something like that up.....

As far as repairs go... the CF strips work very well... I had a Wasp sitting around the garage with a broken fuse... I thin ca'd the fuse then used 3 1/4" wide CF strips on either side to give it strength.... It's holding up fine...

Bad Driver

Hi Paul,

Thanks for your reply ! I really appreciate your offer of a re-design employing the Taco FF methods but I think that if I took your attention away from the Burrito/Cuchillo then the other guys would lynch me

Sorry to be stoopid but when you say a 'Z' cut do you mean a '' or zig-zag cut ? What sort of length of cut would you recommend for best strength ?

I can't remember off-hand the height of the fuse but maybe I'll make it as tall as the 4" sheet allows. I'll save the stick building for later models.

Thanks again,

B.D.

PaulSwany

My Feedback: (45)

I was thinking of a Z cut like a "" below... Use caperters glue to make the joints and make sure the right and left half joints are stagered....

Daryl Martel

My Feedback: (3)

Like Paul said, have no fear using scarfs. I make mine 60 degrees. The steeper the angle the better. I've built a Wasp and a Wasp based profile fuselage for a set of Sig Something Extra wings/tailfeathers using this method. I routinely use scarf joints employing both Titebond or medium CA. Just try to get the joint fit as near to perfect as possible to maximise strength. I've never had a scarf joint come apart and I frequently use this technique on leading edge sheeting - Bad driver, you'll have to do the same for the Wasp leading edge sheeting.

Bad Driver

Thanks for the advice guys.

Any other Wasp tips ?

B.D.

Daryl Martel

My Feedback: (3)

The fuselage is very flexible - too flexible IMO too be using pull-pull. I stiffened mine up by glueing .007" thick by 1" wide carbon fibre tape along the bottom on either side from about the center of the the wing chord to the tail post. I used a 1/2" wide strip of CF on the the top and bottom oh the horizontal stab too stiffenn it up and make it bullet proof. I glassed the wing leading edge sheeting with .5 oz cloth and Z-Poxy finishing resin too toughen it up - I hate repairing holes in 1/16th" sheeting and it added very little weight. I made my elevator pull-pull too. If you fly off of a nicely grassed patch, all you really need is one wheel and a tail skid - you can easily taxi around dragging a wing tip and once you get very little speed up the ailerons are effective enough to bring the wings level on the (short) takeoff run. I have an Irvine .53 in mine - great combo - overkill for sure, but as it's the same size and weight as a .46, why not! Will attach some pix...

Daryl Martel

My Feedback: (3)

Sideways using big heavy duty Dubro servo arm so it extends out past the wing skin.

Daryl Martel

My Feedback: (3)

Used ordinary (cheap) Dubro horns and the thin 2-56 size pull-pull cable and hardware. Has stood up well - I've been flying this thing over two years I figure.

Daryl Martel

My Feedback: (3)

I use plywood for engine bearers and build it so that the engine thrustline remains on the fuselage centreline. Get your engine installed as far back as possible to reduce the need for tailweight. Even with mine this far aft and the battery located towards the back of the wing, I steel needed to add lead to the tail to get the C of G where I wanted it.

Daryl Martel

My Feedback: (3)

The other day I broke my Lexan gear on a bad landing. I was surprised to see it break, but then again it really couldn't flex much either. I used a 1/8th" diameter nose gear I had lying around and a nylon mounting block to make this arrangement. I flew it yesterday and it holds up well. It's light and strong enough to support the weight and taxi around. It's nice to actually have proper suspension action happening again.

Bad Driver

Hi Daryl,

Many thanks for the additional Wasp info - much appreciated.

Hmm, the fuse flex is interesting. As I mentioned in my original post do you think that using carbon fibre cloth instead of the glass cloth in the lamination would overcome this problem ? Did you fit the hard-wood strengthener that runs along the full length of the fuse bottom ? Also (sorry bout this), where would you recommend I have the scarf joint on the fuse ?

Engine thrust, stab strength and leading edge reinforcement all noted I was going to employ the stick-built method for the hori. stab but what I'll probably do now is use some sheet (LE), a spruce strengthener, a bit more sheet and then stick-built. Haven't got the plans handy so am not too sure at the mo.

I wanted the Wasp to be a pretty quick and easy build initially so I don't mind (too much) when I crash it. I have some other designs to work on as my flying abilities (ha ha) improve.

Thanka again !

B.D.

Post Script: Did anyone manage to save the Wasp Plus info ? It's a dead link on the Sirex site. Cheers.

Daryl Martel

My Feedback: (3)

Hi Bad Driver, I don't think putting CF in the middle would help much. The glass or CF would have to go on the outside of the fuselage sides to achieve stiffness. As it's designed with the glass cloth in the middle, it adds strength, not stiffness. You won't see this fuselage breaking behind the wing on a bad landing as many fun fly planes are known to do. I did run a 1/8th" by 3/8th" strip of spruce along the bottom as per plans. Wouldn't hurt to do likewise on the top either. I don't remember where I located the scarf joint on the fuse, but it was forward somewhere. Location not too critical, but Pauls advise about staggering the joints is spot on - personally I would also ensure they run in opposite directions on either side to maximese strength (probably what Paul meant). Re using the stick-built method for the horizontal stab, I did this too and for the ailerons as well. Lots of mods! The Wasp made me a better flyer by allowing me to push the envelope much more than more conventional designs would. You can get more acrobatics in, lower, slower, in a tighter box than with faster designs. The only danger is you may find yourself getting so confident you do riskier stuff down low where there's no recovery room. Mine has had a long life, but there's been plenty of close calls! Have fun with yours - they are a hoot!

OBTW, I don't have the Super Wasp canopy dimensions either, but you can get a pretty good idea of the dimensions from my pix.

Cheers

Bad Driver

Thanks Daryl - I really appreciate your help !

I'm on holiday next week ( ) so lots of building and flying to be done !

All the best,

B.D.