Tony Nijhuis Posted June 6, 2012 Share Posted June 6, 2012 Now here's a pic of the new Vulcan.....one of two sizes,,, the smaller being 48" and the larger being 78". The larger is sorted and will have a couple of 90mm fans or a single 44 size turbine (yes only a single!!!!) The 48" is proving a problem due mainly to it's size. The pic shows the 48" with a couple of 68mm fans, but the weight is creeping up to 6lbs plus due to the complexity of the design and hand launching will become an issues. I have added some micro retracts but the wheels will be too small to prove useful either landing or take off (unless on tarmac) so I'm thinking of ditching the fans on this smaller version and going for a electric tractor and keeping it all very simple just need to gauge the responce from the masses out there so all sensible comments welcome Quote Link to comment Share on other sites More sharing options...
Tony Bennett Posted June 6, 2012 Share Posted June 6, 2012 maybe an electric pusher would look better. Quote Link to comment Share on other sites More sharing options...
Stephen Jones Posted June 6, 2012 Share Posted June 6, 2012 Hi , I reckon a 50 50 split here as there will be plenty wanting the fan and settling for a bungee launch . And at that weight the safest way will be the bungee Quote Link to comment Share on other sites More sharing options...
A.A. Barry Posted June 7, 2012 Share Posted June 7, 2012 I agree with Tony Bennet, EP pusher For C/G would it balnce better with the motor on the Ft or Rear ?? saving adding weight Barry Edited By A.A. Barry on 07/06/2012 00:22:19 Quote Link to comment Share on other sites More sharing options...
Lindsay Todd Posted June 7, 2012 Share Posted June 7, 2012 Presumably the weight increase includes the impact of a spar incorparating the ducts to maintain strength in the airframe. Moving to a pusher format would surely be a retro step for this effort and would be further compromised by increased drag of none functional ducts. I can't help feeling that as Tony suggests a tractor set up is the best compromise for a good performance, that is unless you go pss and chuck it off a cliff - problem solved Quote Link to comment Share on other sites More sharing options...
Colin Bernard Posted June 7, 2012 Share Posted June 7, 2012 My own view is that to have any sort of prop on this beauty would be sacrilege! If it is simply a choice of having a prop driven Vulcan versus needing to use a bungee or dolly, then the latter wins for me. Once it is in the air then there are no props to spoil those long low flypasts. Quote Link to comment Share on other sites More sharing options...
GrahamC Posted June 7, 2012 Share Posted June 7, 2012 I would consider building the small one as a pusher, but not as a tractor. Far be it from me to instruct the great TN on aircraft design (I've learned soo much from building two of your designs) but so you know my reasoning for the answer... Pushers tend to spoil the lines less. A tractor won't look like a vulcan with the iconic nose. A pusher with a spinner in the aft cone probably could be well hidden, especially if you used an inrunner. I understand that pushers are more efficient too. Quote Link to comment Share on other sites More sharing options...
Trex700e Posted June 7, 2012 Share Posted June 7, 2012 I would go for two small pushers on the trailing edge of the wing but give a few hints on the plan to anyone who wants to go EDF? Quote Link to comment Share on other sites More sharing options...
Piers Bowlan Posted June 7, 2012 Share Posted June 7, 2012 I have had a Wren 44 sitting on my bench for the last three years; sacrilege I know! I purchased a plan of Graham Dorschell's 68in Vulcan with a view to heavily modifying it (redesign) to accomodate the Wren. However this would be a big job and I have little time for a project like this. I wasn't particularly bothered by the prospect of a single jet exhaust as I am not a purist, I just wanted to capture the character (wing shape) and turbine sound of this legendary aeroplane. It is exciting that TN has produced a 78in span Vulcan for EDF or Turbine, I have no doubt that it will build well and fly superbly. Can't wait to order the plan and start cutting balsa- I will just have to MAKE the time! As far as the 48" span Vulcan is concerned I would prefer a pusher prop configuration but care would be required for hand launching if inadvertent digit removal is to be avoided! Quote Link to comment Share on other sites More sharing options...
Alan Randall Posted June 7, 2012 Share Posted June 7, 2012 I would also opt for twin pushers.. I have a atand off scale Vulcan made in depron with a single pusher prop, and have no difficulty hand launching that. Quote Link to comment Share on other sites More sharing options...
Keith Simmons Posted June 7, 2012 Share Posted June 7, 2012 Perhaps a single pusher and ditch the retracts for the smaller Vulcan. Have the ducting open from front to rear to reduce drag. Can have twin brushless on the outer engine exhausts. I will go for the larger model and have EDF. Can't wait ... Quote Link to comment Share on other sites More sharing options...
Frank Skilbeck Posted June 7, 2012 Share Posted June 7, 2012 Make the 48" a PSS Maybe the 78" version should be for 2 x Jet Cat P20's or Kolibri's. Keith - keeping the ducting open will increase drag by the way. Edited By Frank Skilbeck on 07/06/2012 14:04:27 Quote Link to comment Share on other sites More sharing options...
Tony Nijhuis Posted June 7, 2012 Author Share Posted June 7, 2012 Some good ideas.......I do like the twin pushers idea......keep them coming Frank you are spot on....if you dont need the ducts....block them up Quote Link to comment Share on other sites More sharing options...
Reno Racer Posted June 7, 2012 Share Posted June 7, 2012 For the smaller 48" one, a twin 70mm EDF for catapult ramp launch. I fear twin pusher props might get a bit finger hungry for hand launching. Very interested in the twin 90mm EDF, assuming it doesn't get too heavy which then means more expensive higher powered fans/lipos etc in that vicious power/weight/duration cyclone. Using cheaper and less efficient HK type lower powered fans would be better, but i guess the AUW would have to be sub 8-9Lbs to get any performance without massive A draw. My 6S Jepe fan is great and kicks out 6.5 lbs (1250W) of thrust for 54A, but that costs a fair bit and two would only give 13lbs of thrust max so I guess at 200 watts/lb the AUW would have to be about 12Lbs. Still I suppose cheaper than a WREN 44! Quote Link to comment Share on other sites More sharing options...
Tim C Posted June 7, 2012 Share Posted June 7, 2012 Stick with the EDF and bungee lauch, props would be sacrilge Quote Link to comment Share on other sites More sharing options...
graham kindberg1 Posted June 7, 2012 Share Posted June 7, 2012 A couple of HK 64 mm 2nd generation fans will pull 1500 watts with the right batteries, do away with the retracts, stay light, and bungee/catapult launch. May not be what the masses would understand, but it would work. Offer several options in the design. I would be happy to cobble one together with the twin fan set up to prove that option. Have done that with the NH Tornado. Regards Graham Quote Link to comment Share on other sites More sharing options...
pete taylor Posted June 7, 2012 Share Posted June 7, 2012 For what it's worth, I think I'd be tempted to adapt the design for twin pusher configuration anyway. Cheers, Pete Quote Link to comment Share on other sites More sharing options...
Chris Bott - Moderator Posted June 7, 2012 Share Posted June 7, 2012 I too think pushers are far less obtrusive than props at the front. Quote Link to comment Share on other sites More sharing options...
Tony Nijhuis Posted June 7, 2012 Author Share Posted June 7, 2012 As for the 48" fan version it's all but finished so the plan is to give it a go anyway, It will work as it has a couple of 68mm Lander fan but that is where the weight has come from i think! I'm thinking I will build another version for prop drive and get the model flying first so i'm comfortable with flight characteristics before bungeeing something untested..... any more comments? PS... The 78" version will have a couple of 90mm Lander fans on 8s lipo so hoping for an AUW of 12lbs should see much better set up Quote Link to comment Share on other sites More sharing options...
A.A. Barry Posted June 8, 2012 Share Posted June 8, 2012 How about using props inplace of the fans, have a slot in the wing for them to turn in, once they where spinning, one would hardly even see them Barry Quote Link to comment Share on other sites More sharing options...
Keith Simmons Posted June 8, 2012 Share Posted June 8, 2012 Sorry about my comment of having a duct Comparing at the weight between the two sizes, ideally the smaller model would be half the weight, (under 3 lbs) and I doubt EDF has enough thrust strength for a hand launch 6 lb model. so props will have to do. Quote Link to comment Share on other sites More sharing options...
Graham Dorschell Posted June 9, 2012 Share Posted June 9, 2012 Hmmmmm Watching with great interest - did my plan help a bit ? Quote Link to comment Share on other sites More sharing options...
Graham Dorschell Posted June 9, 2012 Share Posted June 9, 2012 Quote Link to comment Share on other sites More sharing options...
Tony Nijhuis Posted June 10, 2012 Author Share Posted June 10, 2012 Hi Graham, Yes the plan was helpful but you know its sometime easier to start from sratch especially as i was only using two fan units.....even now I'm still tweeking...... Quote Link to comment Share on other sites More sharing options...
Graham Dorschell Posted June 10, 2012 Share Posted June 10, 2012 Great - I now have a decal sheet made up for XH558 if your interested. Will try and have a chat at the shows . Quote Link to comment Share on other sites More sharing options...
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