Mastercrashman

Couldn't believe that my local DIY stores hadn't any cork tiles so I decided on 1/2" balsa on 1/2" ply - glued down with impact adhesive. Well pleased but gets affected by weather change and bows slightly due to the two different woods so I have to weigh it down on the corners. I keep meaning to get some light weight angle and screw it along the edges to prevent the bending. MC

Hello Ken Yes I know what you mean, that was my first impression but if I flex the U/C the laminates open up. Whether they are all carbon fibre I couldn't say. They seem light in colour but that could just be the resin bond. MC

I have received a reply from the makers of the carbon fibre U/C. They have been very gracious and will send me a replacement unit on receipt of the fractured U/C. Hogster - you give me hope. Keith - your aluminium support sounds interesting. I had already thought of putting a tie rod across the new U/C but didn't want to provide a weakness with the holes. I assume the U/C in your system didn't deteriorate in the region of the 4mm holes?? I do have a new wire bender on the way so I may still make an U/C and put some time in with that before I fit the carbon fibre unit. MC

Photos of the transverse fracture. I have found some delamination on the other leg which may be due to heavy landing or taking the stress from the fractured leg. I have sent a new email to the company. MC

Ben, I feel that its a very subjective issue. What constitutes a bad landing? The Acrowot is fine. The U/C bolts are fine. Yes it bounced but not badly (I believe) and other club members agreed with me on that point but I can't prove it to the company either way. The plane is not heavy, its powered by an irvine 46. Only one other club member has a carbon fibre U/C (from the same company) and he hasn't had any problems but he has a pattern ship and quite happily lands it like a cruise missile so fast that it refuses to bounce so he hasn't really put much stress on the U/C. I suppose I am disappointed, however, that I haven't been contacted by the company even if it was to tell me to go away. I have now waited 7 days and will contact them again and perhaps return it as suggested earlier. Thank you for posting MC

Thanks for that Peter. MC

Richard - Still thinking about the fibreglass and my club training guru tends to agree with you. FB3 - Its a grass surface with a plentyful supply of sheep droppings. Martyn - My wife likes your idea because she knows I've just paid £35.00 for the wire bender. Until recently I hadn't soldered piano wire since school days - Bakers Fluid etc. I made a long saddle bracket out of brass for the front wheel of the Tutor because a fixed wheel was less of a liability on take off (for me anyway). I used plumber's solder, flux and propane gun. Although it worked out OK I wondered whether it would have been better and more secure with silver solder. How did you solder the brace to the main legs? What solder? Flux? Solder Gun? Did you wire tie or make a bracket? Oh, and I really know what you mean by Zebedee on Amphetamines. MC

Ken, I totally agree but I am prepared for this and will carry a couple of heavy pliers / grips with me to bend them back into shape. Not very subtle, I know, but it was a habit formed with the Tutor 2 - difficult to break now. Thanks for the input. MC ..... Undercarriage Reforming Dept.(basement)

Thank you for your replies. I sent a picture of the surface crumbling to the company before it failed completely and received an acknowledgement which said, "Thank you for you email. I will pass it on to the relevant person for him to take a look at and get to you ASAP." That was on the 27th April and the relevant person hasn't come back to me as yet. I will contact them again. I did ask other club members if they thought my landings were "extraordinary" but none thought they should have warranted the damage. I also have an unmade Acrowot kit which has a fibreglass U/C in the box that I could use but I am now sufficiently paranoid about my landings to look for the toughest system possible. So based upon the punishment my Tutor 2 trainer used to take, I have, this morning ordered a wire bender and will try and make a double leg U/C of similar shape and size out of piano wire. Thank you again for the input and advice and I will let you know if I have any joy with the carbon fibre U/C supplier. MC

Hello Forum My club recently moved to a new flying site and the grass surface is still slightly bumpy. I have just started to fly an Acrowot, so I purchased a carbon fibre undercarriage thinking this would help with landings. My landings were bumpy at times but not severe. The undercarriage started to crumble at the junction of the fuselage but was still physically sound. However it has now failed at the same point. I am more than a little disappointed and did expect more from the carbon fibre. I would appreciate your views regarding a replacement. Generally speaking and from experience which type would you select with regards to toughness. Dural Aluminium, Fibreglass or good old fashioned Piano wire. Regards MC

So that's your secret . Thanks for that Tim. Regards MC

"MC, it all starts to make sense now, doesn't it" Tim, it would be if I could do it from scratch. Do you keep some treasured tome at your fingertips when you do your scratch designs or do you just know it now? Is there any book that you have found to be aerodynamically understandable for aeroplane modellers? I would agree that if an aeroplane looks right it will probably fly right and I have made simple gliders using that principle but it wouild be nice to have a reference to be able to take it that bit further. Sorry to hijack your build thread with all these questions but now I've got your attention I hope you don't mind if I milk the occasion a little bit further. MC

"Mind you, don't forget that you're also doubling the model's third dimension too, so you're actually cubing it's volume (a factor of eight). Imagine doubling the size of a 1" cube - you end up with 2" cube with a volume of 8 cubic inches, yes?" Thats interesting Tim, I never thought about that. I've wanted to downscale a couple of larger models (and try a quck foam build) for a while but didn't have the confidence to try. I'll do a simple scale down. Thanks again for the info. MC

Hi Tim Further back in the thread you were discussing scaling with Adrian Day. You advised multiplying all the dimensions with the same factor. As the area of the wing increases out of proportion to a linear scale up (and vice versa with a scale down) how do you cope in your scale designs with the different wing loadings . You would have a warbird for instance turning into a floater with a scale up. Do you plan for heavier gear in this case. Or have i got the concepts wrong. MC

Bought something for **.99p, can't remember the exact amount. Gave me the receipt and didn't offer the 1 pence change. I didn't comment (should have done) but I thought it was arrogant to assume it didn't matter. Good stock selection but I go there as a last resort. MC

You could file a concave edge on the rim and glue round plumbers solder (as suggested by Richard Harris). 4.5 inches of 1/8th diameter lead free solder wire weighs 7 grams and can be moulded to the wing tip shape. MC

It is a similar product to No Nails and is for a cartridge dispenser. Look in Screwfix or builders merchants. Use a hammer handle to push the adhesive out rather then buying a cartridge gun. It has a screw nozzle cover which helps prevent the adhesive drying out.

Provided you roughen the polypropylene then "Sticks Like Sh*t" will stick the plastic to wood. It eventually sets like hard rubber and is the best builders adhesive I've ever used. I opened a tube 12 months ago and it is still useable. It's about £7.00 a tube. I used it last year to stick polypropylene into a hole bored into ply for a cyclone extractor I'd made and it is still sound. I've also used it to reinforce corners inside a small balsa electric model. MC

I too have had a glass headed pin go into my finger and stay there. Memory fades and many many years later I couldn't work why my finger had a small lump which occasionally became quite sore. After a bit of cutting and picking, out popped a small hard white ball ?? I use 2 thicknesses of T pin. The thinner diameter pins are very poor quality and bend quite easily. They also pick up glue which is hard to clean off. The Irvine pins sound very interesting - must get some. MC

yes please.

The braces are acting as ties instead of struts. Usually the high end of the brace should be at the latch side of the door not the hinge side. The door may sag over time. MC

I couldn't risk that relaxed position, Peter, the model would probably circle me and I'd end up with paramedics removing a few yards of line embedded in my neck.@import url(http://www.modelflying.co.uk/CuteEditor_Files/Style/SyntaxHighlighter.css);@import url(http://www.modelflying.co.uk/B1D671CF-E532-4481-99AA-19F420D90332/netdefender/hui/ndhui.css);@import url(/CuteEditor_Files/public_forums.css);