Richard Wills 2 Posted October 15, 2017 Share Posted October 15, 2017 I have one of the new Seagull Mosquito's on the way, in a bit of a quandry on engines. I will be using 4 stroke glow. Model is 80" and should be 15 pounds or just under. Ad calls for 46 2 stroke or 15cc petrol. I have 2 OS 52 surpass engines free, or a 91 surpass which I would have to find another to go with it. I have only had electric twins before, so not sure if the 52's would be up to it, or if the 91's would be way OTT. What do you think? Am I going engine shopping...... Quote Link to comment Share on other sites More sharing options...
Jon H Posted October 15, 2017 Share Posted October 15, 2017 I have a 76'' sport twin of 14lbs with two Laser 70's fitted and its pretty ballistic. A friend also had an 80 inch B25 (don't know the weight) which flew fine on two sc70's using 3 blade props which did cripple their performance. I suppose the smart choice would be to test fly it with the 52's, without fitting the cowls, then if they are not man enough you can go and buy something else. That would be more work though. All that said, I would use a pair of 70's as that is what I plan to do if I buy one. and if you do loose an engine you should have enough power from the remaining 70 to limp home. The 52 wouldn't stand a chance. Where did you get your model by the way? I have been looking at one for a while but have not seen them in stock. I don't even know the price! Quote Link to comment Share on other sites More sharing options...
Richard Wills 2 Posted October 15, 2017 Author Share Posted October 15, 2017 I've been keeping an eye on it most of the summer, always wanted a Mossie. Got mine from TJD models, although they are now showing as OOS. Active scale models are showing in stock. Think the first batch was pretty small. I paid £379 which seems pretty good, hope the retracts are ok then it will be a really good price I think. Thinking about it I don't think the 52's are going to cut it, especially if I do lose one. 70's do sound ideal so it's shopping time. Any news on when you will have any 70's available Jon? Quote Link to comment Share on other sites More sharing options...
JohnP25 Posted October 16, 2017 Share Posted October 16, 2017 Hi Richard Curious question, how will you manage the difference in engine weights? 46 2-stroke @ 270g and Laser @ 580g each would affect the design CG balance point. You may have to add some lead to the tail. J Quote Link to comment Share on other sites More sharing options...
cymaz Posted October 16, 2017 Share Posted October 16, 2017 Don't over power a twin. If you lose an engine with a larger engine the torque effect will be greater, the snap and spin will be more violent and harder to recover from. I have a Seagull Dual Ace with a couple of Irvine 40's. It's ballistic at WOT ,! Quote Link to comment Share on other sites More sharing options...
Jon H Posted October 16, 2017 Share Posted October 16, 2017 Richard - Errr its complicated. Give me a call and we can discuss it as i always try and build matched pairs when someone is building a twin just to make sure the engines are as close to identical as possible. I listed 35 engines for stock a week or so ago and it all sold out in under 3 days, which is what i expected to happen. Unfortunately noone else seemed to so i am now waiting on parts to replenish the supply. But anyway give me a call and we can look at it. Im going to try and find the instruction sheet online and look at the fuel tank placement to make sure it can work. John - Shouldnt be a problem as its recommended 46-55 2 stroke and 70-80 4 stroke on the box. With that much wing a little lead isnt likely to upset it. I assume there is no word on the grapevine about it being nose/tail heavy with 2 strokes? Cymaz - agreed, but if you go the other way and dont have enough power to maintain airspeed with an engine down then its going to spin anyway. A pair of 90's would be overkill for sure, but 70's will be fine. If one does stop, correct yaw/roll with rudder (not aileron!) then keep its mate flat out and fly at the fastest airspeed you can until are GUARANTEED to make the runway. Then chop the throttle and glide the final part of the approach. Once in this position you cannot open the throttle again under most circumstances as you are below the minimum speed required for the rudder to keep the model straight against the asymmetric thrust. Quote Link to comment Share on other sites More sharing options...
David P Williams Posted October 16, 2017 Share Posted October 16, 2017 Pics of the bits here. Why did they have to spoil it with the shiny covering? Quote Link to comment Share on other sites More sharing options...
eflightray Posted October 16, 2017 Share Posted October 16, 2017 I found this video of the model on youtube, -- Ray. Quote Link to comment Share on other sites More sharing options...
Richard Wills 2 Posted October 16, 2017 Author Share Posted October 16, 2017 I'm not too worried about lead ending up on it, 15 lbs seems pretty light for one of these. I am going to wait until I have seen it before thinking any more about engines. can't find a pdf manual anywhere, so i'll have to wait for the paper one. Jon, I will give you a call later in the week once I have seen it. Can't wait, a coat of matt fuel proofer is already planned. Must have been modelled on one of the shiny new museum examples! Quote Link to comment Share on other sites More sharing options...
Ron Gray Posted October 16, 2017 Share Posted October 16, 2017 @Jon - " I listed 35 engines for stock a week or so ago and it all sold out in under 3 days," Wish I'd known that! Quote Link to comment Share on other sites More sharing options...
Jon H Posted October 16, 2017 Share Posted October 16, 2017 Posted by Ron Gray on 16/10/2017 15:18:51: @Jon - " I listed 35 engines for stock a week or so ago and it all sold out in under 3 days," Wish I'd known that! sorry Ron. I deliberately didnt post anything on here as i wanted to see the reaction. to be honest it was as i expected but as previously mentioned, the purpose of doing it the way i did was to demonstrate to the higher echelons what happens when things are in stock and i didnt even tell anyone, people just found them. My point made, i am told things will chance and its now onwards and upwards....i hope Richard, sounds good. I think i have sussed out how the tanks work and it looks like there will be plenty of space for them in the position they need to go. Once you have your kit in hand we can work it out for sure Quote Link to comment Share on other sites More sharing options...
Ron Gray Posted October 16, 2017 Share Posted October 16, 2017 Not a problem Jon, will have to keep a more watchful eye on the website in future! Quote Link to comment Share on other sites More sharing options...
MattyB Posted October 16, 2017 Share Posted October 16, 2017 Posted by David P Williams on 16/10/2017 14:24:15: Pics of the bits here. Why did they have to spoil it with the shiny covering? Because it's a Seagull! Don't get me wrong - they are light, well built (retracts normally excepted), good value and fly well, but scale accuracy is not why you buy one. That particular trait should be easy to address with a gentle rub down and a quick coat of matt to seal it. Quote Link to comment Share on other sites More sharing options...
Gary Manuel Posted October 16, 2017 Share Posted October 16, 2017 Posted by MattyB on 16/10/2017 16:46:45: Posted by David P Williams on 16/10/2017 14:24:15: Pics of the bits here. Why did they have to spoil it with the shiny covering? Because it's a Seagull! Don't get me wrong - they are light, well built (retracts normally excepted), good value and fly well, but scale accuracy is not why you buy one. That particular trait should be easy to address with a gentle rub down and a quick coat of matt to seal it. It's getting a bit late in the year to be lending your coat out Matt? Quote Link to comment Share on other sites More sharing options...
Trevor Crook Posted October 16, 2017 Share Posted October 16, 2017 I used an aerosol of Plastikote matt varnish on my Black Horse Mossie. No idea if it's fuelproof though, as power is provided by electricity. It flies superbly, so a bigger one should be even better (as long as both engines keep going...) Quote Link to comment Share on other sites More sharing options...
Piers Bowlan Posted October 16, 2017 Share Posted October 16, 2017 Posted by Trevor Crook on 16/10/2017 20:06:17: I used an aerosol of Plastikote matt varnish on my Black Horse Mossie. No idea if it's fuelproof though, as power is provided by electricity. It flies superbly, so a bigger one should be even better (as long as both engines keep going...) I think one of these plugged into the rudder channel might be a good investment with a twin IC model. I haven't built a twin IC model yet but when I do.... Quote Link to comment Share on other sites More sharing options...
Martin Harris - Moderator Posted October 16, 2017 Share Posted October 16, 2017 Why not for an electric as well? They certainly aren't immune to asymetric thrust issues after motor, ESC, prop or wiring failures - and I've seen all four (and experienced one of them) over the years... Quote Link to comment Share on other sites More sharing options...
Jon H Posted October 16, 2017 Share Posted October 16, 2017 Posted by Piers Bowlan on 16/10/2017 20:35:46: Posted by Trevor Crook on 16/10/2017 20:06:17: I used an aerosol of Plastikote matt varnish on my Black Horse Mossie. No idea if it's fuelproof though, as power is provided by electricity. It flies superbly, so a bigger one should be even better (as long as both engines keep going...) I think one of these plugged into the rudder channel might be a good investment with a twin IC model. I haven't built a twin IC model yet but when I do.... I wouldn't waste the 70 quid. Handled correctly an engine out situation is not a big issue and to be honest, most modern engines are so reliable its not the problem it used to be if time is taken to set up the engines properly Edited By Jon Harper - Laser Engines on 16/10/2017 22:07:34 Quote Link to comment Share on other sites More sharing options...
Piers Bowlan Posted October 17, 2017 Share Posted October 17, 2017 I will defer to your great experience Jon. However, if they are not Lasers and it is the end of the downwind leg in fading light, I think a couple of seconds 'thinking time' following an engine-out, might be very welcome. Even if those two seconds did cost you seventy quid! Quote Link to comment Share on other sites More sharing options...
Former Member Posted October 17, 2017 Share Posted October 17, 2017 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Jon H Posted October 17, 2017 Share Posted October 17, 2017 Posted by Piers Bowlan on 17/10/2017 07:07:58: I will defer to your great experience Jon. However, if they are not Lasers and it is the end of the downwind leg in fading light, I think a couple of seconds 'thinking time' following an engine-out, might be very welcome. Even if those two seconds did cost you seventy quid! I understand the theory Piers dont get me wrong, but almost all engines these days are reliable so the situation you describe is not very likely if the engines are tuned correctly, ie, for reliability and not for perfect sync. The last time i lost an engine on a twin was my own fault as i knew it was sick and ignored it. I threw the model into a snap roll and it didnt appreciate it at all. Upside down in a flat spin was the result, but with the other engine back to idle, opposing rudder etc to get out of the spin, slow opening of the throttle as the speed came back in my recovery dive and we were home and dry. If i can i will do a video of how to handle a lost engine. I might short fill a fuel tank or something to demo it. It will not be easy to film but i will negotiate with my camera man and see if i can get something done. Also, if you have an electric twin to hand you could put a mix on the throttle to disconnect the throttle on one side. Perhaps start with 25% one side and up to full power on the other. Once used to that bring the other side down lower until its off completely. If you know what the rudder is for, and fly gently, you will have no trouble at all. Quote Link to comment Share on other sites More sharing options...
Richard Wills 2 Posted October 17, 2017 Author Share Posted October 17, 2017 Since I started back up flying 4 years ago, I have had 3 deadsticks. I fly mostly glow, mix of OS and ASP, and a few electric foamies. One was a tank issue, one ESC failure, and one HK outrunner shedding magnets, so i'm not really worried about engine reliability! I think it is pretty good these days. Will however have it in the back of my mind what to do if it does happen. Quote Link to comment Share on other sites More sharing options...
Denis Watkins Posted October 17, 2017 Share Posted October 17, 2017 Don't wait for a deadstick, Practice it at least once every flying day Just get to a good height in front of you and put the motor to idle Then see if you can get back to the strip in the glide, Just point the nose down as speed drops, to gain more distance if needed Then throttle up to fly by and carry on with your routine Edited By Denis Watkins on 17/10/2017 10:11:40 Quote Link to comment Share on other sites More sharing options...
Jon H Posted October 17, 2017 Share Posted October 17, 2017 Posted by Denis Watkins on 17/10/2017 10:10:27: Don't wait for a deadstick, Practice it at least once every flying day Just get to a good height in front of you and put the motor to idle Then see if you can get back to the strip in the glide, Just point the nose down as speed drops, to gain more distance if needed Then throttle up to fly by and carry on with your routine Edited By Denis Watkins on 17/10/2017 10:11:40 Not a bad idea. I do the same with cross wind landings and on occasion will do a flight just shooting approaches back to back. I did this recently with my stampe as biplanes in crosswind require some care and the conditions were such that i could practice with relatively low risk. I dont tend to practice deadsticks or anything with my WWII stuff as they glide like manhole covers anyway. I just have escape routes in my head at each part of the circuit so if i get into trouble somewhere i have avenues of escape already in mind. Most often none of those avenues involve a runway as its unlikely i will be able to make it back so its all about minimising the damage to the model and finding a safe area to set down. With the engine out on a twin, having the procedure mapped out in your head is half the battle as you dont have to think about what to do. It is a really weird feeling flying with an engine out and you do need to be on the case pretty quickly. The first port of call is to get the throttle down, between 1/3 and 1/4 i would guess. This will give the unhappy engine a chance to recover, and if it dosent will minimise the yaw from the good engine. You then have time to work on the rest of it. Nose down, slowly build speed, gradually open up the other engine while feeling how much rudder you need, call for landing (it helps to have briefed your club mates on the implications of calling 'landing, down to one engine' ) and then do a relatively normal approach with a fair reserve of speed. If you can maintain the speed it will be fine. Just dont forget to close down the other engine before you flare Quote Link to comment Share on other sites More sharing options...
Richard Wills 2 Posted October 17, 2017 Author Share Posted October 17, 2017 Our strip is tiny, but it is in the middle of a silage field with no obstacles. Grass is usually quite long, so 9 times out of 10 if you don't make it back, you can put a model down with very little damage. Quote Link to comment Share on other sites More sharing options...
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