John Timmis

Hi everyone, Hope everyone is well & busy building. Progress on the Vampire is steady rather than rapid, but there is no rush. I try to do a bit every day to keep it moving forward. All the various components are done so now it's time to start assembling them all. Should begin to look like a Vampire. The fuselage was sheeted round the nose & the belly, rather than planking. The trick with ammonia helped to get the wood round the double curvature. The tail booms were built with a vertical .5mm ply diaphragm from wing leading edge to tail. The idea is to make it easy to keep everything aligned during assembly. Cheers John

Hi everyone, the ducts. As we all know, ducted fans are muck less efficient than props. It seemed to me that getting the ducting right was an essential, & also very interesting part of model. Not having designed an EDF before, I read around on this & the other model forum. The accepted wisdom seems to be; ducts should be as straight & unobstructed as possible, avoid sharp bends & changes in direction, a rounded duct inlet is better than a sharp inlet, losses a greater in long ducts. The sizes of the inlet & outlet are critical & are based on the FSA (fan swept area). The inlet needs to be 100% FSA while the outlet can be reduced a bit , from memory 80 %. As shown in the photos the ducts were molded from glassfibre ( glass cloth & epoxy resin, the same stuff I use for finishing). So, here is 'Here is how I done it" The molds are made from pink foam. They were profiled on the bandsaw, templates for the inlet & outlet glued to each end & then the bit in the middle was cut & sanded to a smooth profile. The shaped molds were then covered in solarfilm. Several laminations of glass cloth & epoxy rein were applied. While the moulding was still in its green state it was slit down one side & rmoved & then replaced on the mould to cure. The cut edges were glued with cyano & then another layer of glass. Hope it all makes sense. cheers John

Hi Steve, everyone, Thanks for your comments Steve, glad that you like it. These early jets have always been favourites of mine, takes me back to when I was a lad. I remember reading about PE Norman"s early ducted fan models back in the 50's. I think I first saw edf at the Western Park show about 15 yrs? ago. Anyway that's what inspired me to take up RC again after a 25 year layoff during which time I was involved in schools karting & full size gliding. Back to the model. Some progress has been made. The top wing skins have been fitted, the tail booms have hade the sides glued on & shaped, the elevator snake has been installed. The elevator servo has been fitted in the wing root. Really it's a case of getting all the various bits ready for a final assembly. Looking at the fuselage photos. The fuselage behind the fan frame is all .4mm ply. The rear duct is a short cylinder & then a truncated cone to the exhaust. In front of the fan frame, the fuselage is a basic box structure of 1/4 sq balsa with additional formers to make up the outside profiles. It's certainly not a typical fuselage. As far as i can remember the build sequence was first to build the rear duct with the fan / stub spar frame flat on the building board & the duct vertical. The forward fuselage is an ordinary balsa frame structure. These were then glued together & the wing root ribs added. The wing roots were then built on. Altogether a bit involved & care needed to ensure a straight fuselage. Into all this the glassfibre ducts needed fitting. Something of a jigsaw puzzle. More about the ducts nex time. Cheers John

Hi everyone hope you are all well & finding some modelling time to get on with your projects. Here are a couple more photos of the original model. There were four issues I wanted to improve on the new model: 1 the rather untidy radio instalation with its multitude of hatches, 2 The inconvenient battery connection, the lead had to be threaded through & the large hatch removed for each flight, 3 a better & less complicated fuselage construction, 4 Move the fan forward to remove the need for lead in the nose. Positives were : it did fly well, looked good in the air, scale size intakes , no cheat holes , only the exhaust size slightly enlarged. Next time I'll show some progress on the new model. cheers John

Hi Gordon, everyone, Yes it will be good to get this one finished. My first Vampire was made 9 years ago .It was my first attempt at an own design EDF. It flew very well, the glide seemed to go on for ever, it even had the characteristic Vampire whistle. For several years it hung on the garage wall until last year I decided to fly it again. Unfortunately I forgot to put in the extra lead in the nose. DO'NT FORGET THE PRE FLIGHT CHECKS, Say no more. Model specs; 49" wingspan, 70mm wemotec fan, 4s 3200 lipo. I think the weight was in the region 31/4 lbs but it was a long time ago. Cheers John.

HI Thi present enforced isolation does mean that there is time available for building activity. With the Chiltern just about finished , apart from a few details, it seems like a good time to pick up some unfinished projects. The first one is an own design EDF Vampire. This has been gathering dust for about the last 6 or 7 years. It was put aside when I joined in with Danny's Chipmunk build. Most of the construction has already been done so this is where I am at the moment. This is actually the 2nd Vampire I have made, but more of that later. cheers John