Hello Kate. I am currently building a carbon-fibre based racing sportscar (own design). We use machined dural 'bobbins' to accept the various threads in the chassis. These are bonded into the carbon panels using a high-specification adhesive. Where high temp's are involved, it's best to source the c...

Thanks Tinus. They look like they have the right sort of products / engineering expertise I'm looking for.

I've sent them an email enquiry to see if they can help...
Dave

Thanks Paul, I have spoken to Solo in the past and they seemed reluctant to move away from their standard offerings. They do make nice 'ground-adjustable' hubs though which is tempting ! I think I may well have to lay-up some blades to a standard design unless something else turns up. I'm a bit worr...

Steve - glad to hear the safety side is up to scratch ! I wonder if there's any scope to move engine /cowl further forward a few mil's ? I had to do this recently on an electric conversion and found that around 4-5mm did the trick without spoiling the scale effect and better than carrying all that d...

Steve - just as a safety feature, make sure that there is no water / moisture etc. trapped in the bottom of the tin before putting the solid lead in. I use your method too, plus, I use some heat-protective gloves (same as for putting logs in the wood-burner). Lead splatter /burns can be nasty. Also,...

Does anyone know where I can find some large diameter prop blades ? The overall (scale) diameter is some 39". I need one tractor and one pusher blade set for the contra-rotating set-up (3 blades to each hub). Ideally, I would like ready-balanced 'carbon' blades but a good quality wood set would...

Thanks for the input on full-size Chris. Rob - I've had a look at my Tx and there's a rotary knob on it with a full 270 deg's of travel. I like the simplicity approach and I reckon that this knob could be accidentally nudged in flight without any ill-effects ie with wing-fold / unfold at the extreme...

Hi Rob - thanks for the reply, I guess the main problem with a pure transmitter-based interlock for the u/c 'down' switch position would be that the wings could still be folded during take-off and landing ? I had in mind some sort of oleo leg extension sensor to give the following control logic :- M...

I wonder if more experienced members could advise on whether to use electric or pneumatic actuation / locking for my 1/4 scale Westland Wyvern. The various mechanisms are as follows :- Retractable Main gear Retractable and steerable tailwheel Double wing-fold (mid panel and tips) Power canopy open /...

A quick update on progress : The Mk 1 gearbox contained a fatal flaw in the tooth design. This has now been identified, corrected and a quote received for a new design. The fault was actually a geometrical one (by me, not the supplier) and it involved the teeth spacing of the internal ring that reve...

Thanks for the engineering contact David. As soon as I've finalised the design I'll make some detail working drawings and get in touch...
Dave C

This is a cut-away of the full-size pitch-change system - needless to say the 1/4 scale version will be somewhat simplified !

Hi Keith I'm new to jets - did you find the cause of the flame-out ? I need to learn about these things ! ps also found the same handling quirk on my PC Flight Sim' - just added more "thrust-to-weight" so the lower throttle settings leave more rpm on. Don't know if this will work in 'real ...

The Mk 1 contra-gearbox is nearing the end of it's test life. The rear prop has been repaired twice and I have now consulted with a specialist gear manufacturer for some quotes and extra assistance with tooth profiles, gear ratios etc. Lessons learnt so far :- 1. Wooden mock-ups are great for gettin...

Robin - thanks for demystifying this. I knew that the last 2 digits related to thickness but was not aware of the meaning of the others.

I will certainly look at, and study, the other programs and files that you mention...
Dave

Thanks Chris, Robin - I see that I shall have to make myself more aware of the contents of the LMA website ! Quick question : In the Public Domain Aerofoil listings (Abbott & Doenoff), it shows two sets of ordinates for the 65-212 section (which are quite different) and none for the 65-214...do ...

Hi Chris - the two NACA sections that you mention - were they for another Wyvern model or, the full-size perhaps ? (The gearbox info' is very useful. I also found this a while ago...it incorporates the reduction gear as well as the main prop drives and reversing gears. I also have a cutaway of the R...

Hello David Making a good recovery thanks, but, the workshop is still a bit too cold for serious build sessions. Still shaking the bugs out of the contra-box design but am now close to ordering the metal gearset from a specialist supplier. So far, I've only looked at the Wren 44 and Jetcat TP's. One...

Thanks for the tip on aero' washout Phil. I had considered this but, don't yet know enough about the selection criteria for the two different sections - root and tip. I'll have to start reading "Abbott & Doenoff" again ! On my Phoenix RC flight sim' there's a Bearcat (nearest I can fin...

Thanks for the replies so far - looking through my full-size tech file, the root incidence is set at +1degree. By visual estimation of a 3-view, the tip TE looks to be about 1 to 1.5 degrees above fuselage datum. So, I estimate about 2-2.5 degrees of overall washout. The test pilot's reports (Harald...