Simon Roberts Posted October 2, 2009 Share Posted October 2, 2009 Ive got a Seagul Jumper 25 which comes with a SC25 and my instructor has always said is very underpowered and had nothing in reserve for when needed, now he said to put a .40 in it of some kind, which i have done (an Irvine .40ABC MkIV) and ive had to ad 80grams of weight to the rear to get the CofG right again, will this be ok or does it sound a lot? Quote Link to comment Share on other sites More sharing options...
ken anderson. Posted October 2, 2009 Share Posted October 2, 2009 hello simon-i think that with the irvine in your jumper 25-you will have gone from milk float to formula 1........the 80 gram's seems a lot to put in the tail...i would check out what you have been told...under powered for the instructor may well be enough for you to learn with...i think you will find the jumper will be a different kettle of fish to handle now and a lot heavier........... ken anderson.......... Quote Link to comment Share on other sites More sharing options...
Simon Roberts Posted October 2, 2009 Author Share Posted October 2, 2009 I think was a case of there is no power in reserve to get out of a situation, he said flys but would be better with a bit more power as can always throttle back. I'll see what he says about the weight on Sunday (i can always put the .25 back in) if the weather is fine, not looking good at the moment Cheers Ken Si Quote Link to comment Share on other sites More sharing options...
Marko Posted October 2, 2009 Share Posted October 2, 2009 Hi Simon if you built this plane yourself check the instructions to see if there are 2 c of g points at 55" wing its not a small plane and l would'nt put a 25 on it, after all the plane can have a 25/32 or 30 4 stroke and all makes are not the same weight ,your 40 sounds a good choice . with maybe a good 10/6/ prop, how did you ballance the plane to arrive at it needing 80g on the tail you might fly better with a slighty nose heavy plane happy flying .......................mark Quote Link to comment Share on other sites More sharing options...
Simon Roberts Posted October 2, 2009 Author Share Posted October 2, 2009 I got the info from the Manual Mark, it can be found Here if you want to have a look.Edited By Simon Roberts on 02/10/2009 20:10:59 Quote Link to comment Share on other sites More sharing options...
andy watson Posted October 2, 2009 Share Posted October 2, 2009 I learned on a Jumper 25, and it flew perfectly on an OS 46. I have seen a couple with 25s up front, and every single one has struggled for power. Better to fly on 1/2 throttle with the bigger engine than to not have enough. I would say that the instructions are dire, but I epoxied 2 bolts in the tail of mine to get it to balance- approx 50g if I remember correctly. Remember that you have extra power, so the extra weight isn't an issue. Get the C of G spot on and it flies like a dream. Quote Link to comment Share on other sites More sharing options...
Simon Roberts Posted October 2, 2009 Author Share Posted October 2, 2009 Yeah ive just re done measured the CofG and its now down to 40Gram as i was a doofus and didnt read instructions properly! Hoping this Irvine will make a differenct to her, shes been good so far!! Quote Link to comment Share on other sites More sharing options...
Marko Posted October 2, 2009 Share Posted October 2, 2009 Nice one Simon you might be able to get it better ...try moving the the batt back if you can you will amazed how a few (cm)s make ive a low wing plane where the batt is under the wing bolt plate try with velcro first before you glue, try anything its better than adding ballast !!!!!!!!!...............mark Quote Link to comment Share on other sites More sharing options...
Simon Roberts Posted October 2, 2009 Author Share Posted October 2, 2009 Cheers for the help guys, got it at 30Grams after noving the Batt pack right back and now feel very happy Roll on Sunday! Quote Link to comment Share on other sites More sharing options...
Mowerman Posted October 3, 2009 Share Posted October 3, 2009 I had a Jumper 25 with Irvine 46 needed lots of ballast in the front to get ballance correct even with the rx battery as far forward as I could get it. Flew well enough but landing was too fast for me so I sold it. Quote Link to comment Share on other sites More sharing options...
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