Andrew Moore 7 Posted July 1, 2018 Share Posted July 1, 2018 Anyone come across a MaxThrust Riot XL that flies great around 1/2 throttle but when anything higher is applied it causes a massive rate of climb ?? Cant see it being a CG issue as only really one place battery can go and its a correct size. Possible engine thrust issue ? Not enough downthrust - really not sure. Thoughts ? Quote Link to comment Share on other sites More sharing options...
Gary Manuel Posted July 1, 2018 Share Posted July 1, 2018 Greater lift due to greater airspeed? Quote Link to comment Share on other sites More sharing options...
Kim Taylor Posted July 1, 2018 Share Posted July 1, 2018 Posted by Andrew Moore 7 on 01/07/2018 17:27:01: Anyone come across a MaxThrust Riot XL that flies great around 1/2 throttle but when anything higher is applied it causes a massive rate of climb ?? Cant see it being a CG issue as only really one place battery can go and its a correct size. Possible engine thrust issue ? Not enough downthrust - really not sure. Thoughts ? I wouldn't think that this was a guarantee of the c of g being correct - sounds like it could be too far forward but the only way to be sure is to mark it on the wing and lift it on your fingertips if you have nothing else you can do it with. Kim Quote Link to comment Share on other sites More sharing options...
john stones 1 - Moderator Posted July 1, 2018 Share Posted July 1, 2018 Depends, what does the model say, it got up trim in elevator, hows it behave when you chop throttle ? Quote Link to comment Share on other sites More sharing options...
Denis Watkins Posted July 1, 2018 Share Posted July 1, 2018 This model Andrew, is effectively a high winger, with almost a flat bottom wing, and does offer higher lift with airspeed. The plus side is low speed handling is improved. A symmetrical wing more readily increases speed without too much rise in the nose, But low speed handling is reduced. All a compromise, and do check the C of G and the up trim as the lads suggest Quote Link to comment Share on other sites More sharing options...
Frank Skilbeck Posted July 1, 2018 Share Posted July 1, 2018 I needed some lead at the front of the battery compartment on mine, flew nice then. Quote Link to comment Share on other sites More sharing options...
Alan H Posted July 2, 2018 Share Posted July 2, 2018 My standard size Riot had similar characteristics, fixed by adding some downthrust. Quote Link to comment Share on other sites More sharing options...
Andrew Moore 7 Posted July 2, 2018 Author Share Posted July 2, 2018 My question was actually for a friend, the last two comments are very interesting as hes also had to add weight to the nose and add more downthrust. Surely the manufacturer should have it sorted as an ARTF ? Quote Link to comment Share on other sites More sharing options...
The Wright Stuff Posted July 2, 2018 Share Posted July 2, 2018 Posted by Andrew Moore 7 on 02/07/2018 11:45:40: Surely the manufacturer should have it sorted as an ARTF ? Ha ha ha... Sadly, not the case. Some manufacturers are better than others, but unfortunately, it pays to never assume this... Quote Link to comment Share on other sites More sharing options...
The Wright Stuff Posted July 2, 2018 Share Posted July 2, 2018 You say a massive rate of climb, but what is the attitude during that climb? If the nose rises suddenly when the throttle is opened, then it is more likely to be a lack of down-thrust than if the nose remains pointing forward, but the plane rises anyway... Quote Link to comment Share on other sites More sharing options...
Tim Flyer Posted July 2, 2018 Share Posted July 2, 2018 I have flown them a few times buddying for a beginner. I would say they are a reasonable trainer type plane but not nearly as nimble as a Wot 4 foam E. However being big they are easy for orientation and are very easy to land . I didn’t really have a major issue with the climb on throttle as it was being used as a trainer, but as said a down thrust correction could easily be made . I think the name of the plane is a bit over the top for the actual performance though. Quote Link to comment Share on other sites More sharing options...
Tim Ballinger Posted July 2, 2018 Share Posted July 2, 2018 Had mine for over 2 years now. Used it to get back into flying as a trainer and now it is my go to fun plane . Never had the problem as described and never added weight or changed down thrust. Cg is pretty much where it was meant to be as far as I recollect. I have it trimmed straight and level for about 3/4 throttle so perhaps that makes the difference. That’s with a 4S 3200 pack btw. Tim Edited By Tim Ballinger on 02/07/2018 16:28:54 Edited By Tim Ballinger on 02/07/2018 16:31:45 Edited By Tim Ballinger on 02/07/2018 16:32:31 Quote Link to comment Share on other sites More sharing options...
AVC Posted July 2, 2018 Share Posted July 2, 2018 It sounds like (lack of) down-thrust issue... Quote Link to comment Share on other sites More sharing options...
PatMc Posted July 3, 2018 Share Posted July 3, 2018 Posted by Andrew Moore 7 on 02/07/2018 11:45:40: My question was actually for a friend, the last two comments are very interesting as hes also had to add weight to the nose and add more downthrust. Surely the manufacturer should have it sorted as an ARTF ? Adding weight to the nose will make the problem worse but it may be necessary to the cg forward if the elevators are too sensitive. But if the model flies well at half throttle why does he open it further unless he wants it to climb steeply ? Quote Link to comment Share on other sites More sharing options...
MattyB Posted July 3, 2018 Share Posted July 3, 2018 To test the CG climb up to height, close the throttle and then do the dive test... (ignore that this is noted for a glider, it will work with any fixed wing) If you see behaviour A, your CG is too far forward - bring it back then do the CG test again, repeating until you get B or D, then go to full throttle from level flight again. If it still pitches up and climbs significantly it is a lack of down thrust that is causing the issue. Edited By MattyB on 03/07/2018 10:57:08 Quote Link to comment Share on other sites More sharing options...
Andrew Moore 7 Posted July 3, 2018 Author Share Posted July 3, 2018 Thanks for all of the help & advise - plenty to check-out & have a go at. Yes, my friends plane plies ok at half throttle but really need it flying well throughout the rev range (like mine do) - dont want it taking off to the moon when transitioning from 1/2 to full throttle Quote Link to comment Share on other sites More sharing options...
Geoff S Posted July 3, 2018 Share Posted July 3, 2018 I'm a great fan of the smaller Riot. As supplied and with the recommended throws it's a very tame machine but increasing the throws and removing the lump of steel at the front (ie moving CoG back) transforms it into a fun machine in any flyable wind. I've never noticed any tendency to climb excessively with increased throttle even with the CoG moved back (not sure where it is except that it's OK) and I haven't changed the thrust angle. So whatever problem you have with the bigger version doesn't seem to be echoed in the smaller. btw I'm on my 3rd. I wore out the first and it eventually met its end when somehow (I still don't know how) ended up with reversed ailerons. The second I inadvertently flew into an isolated low cloud and it few away. My current one is called a Devil but it's the same model. So 100s of flights on Riots. Geoff Quote Link to comment Share on other sites More sharing options...
PatMc Posted July 4, 2018 Share Posted July 4, 2018 Posted by MattyB on 03/07/2018 10:28:31: To test the CG climb up to height, close the throttle and then do the dive test... (ignore that this is noted for a glider, it will work with any fixed wing) If you see behaviour A, your CG is too far forward - bring it back then do the CG test again, repeating until you get B or D, then go to full throttle from level flight again. If it still pitches up and climbs significantly it is a lack of down thrust that is causing the issue. Edited By MattyB on 03/07/2018 10:57:08 Matty, there's no need to do the dive test with a power model. The dive with a glider is done to speed the model up in the same way as opening the throttle with a power model. Simply set the throttle to fly steady straight & level for a few seconds then open to full throttle with no change to elevator trim. Consider the subsequent change in flight path as per your diagram but with path "B" drawn as S&L & the other paths diverging from "B" by the same amount shown in the diag. Quote Link to comment Share on other sites More sharing options...
PatMc Posted July 4, 2018 Share Posted July 4, 2018 Posted by Geoff Sleath on 03/07/2018 11:28:50: I've never noticed any tendency to climb excessively with increased throttle even with the CoG moved back (not sure where it is except that it's OK) and I haven't changed the thrust angle. Geoff, any excessive climb is an indication of the CG being too far forward. Quote Link to comment Share on other sites More sharing options...
Andrew Moore 7 Posted July 4, 2018 Author Share Posted July 4, 2018 Very little if any room for CofG movement on this model unless non-standard batteries etc Quote Link to comment Share on other sites More sharing options...
J D 8 Posted July 4, 2018 Share Posted July 4, 2018 On one model I have [ it is over powered ] I have mixed in a bit of down elevator as throttle is opened to prevent this "ballooning" as it was once known. Quote Link to comment Share on other sites More sharing options...
PatMc Posted July 4, 2018 Share Posted July 4, 2018 Posted by Andrew Moore 7 on 04/07/2018 09:46:39: Very little if any room for CofG movement on this model unless non-standard batteries etc If you want to move the cg rearwards buy a strip of wheel balance weights & stick them as required on the fuselage just under the tailplane. If nose weight is needed, some lead sheet bolted securely in the nose area. Posted by Andrew Moore 7 on 03/07/2018 10:43:37: Thanks for all of the help & advise - plenty to check-out & have a go at. Yes, my friends plane plies ok at half throttle but really need it flying well throughout the rev range (like mine do) - dont want it taking off to the moon when transitioning from 1/2 to full throttle He could always reduce the overall power by fitting a smaller dia prop. Edited By PatMc on 04/07/2018 21:14:54 Quote Link to comment Share on other sites More sharing options...
Wilfried Lenauer Posted October 18, 2019 Share Posted October 18, 2019 Am looking for a propeller 12x6 for Riot. When listing the spare parts of the company Max-Thrust .. he is listed as sold out. "Normal" 12x6 E do not fit. Who knows where to get these propellers? Thank you for info Edited By Pete B - Moderator on 18/10/2019 18:55:15 Quote Link to comment Share on other sites More sharing options...
Pete B Posted October 18, 2019 Share Posted October 18, 2019 Posted by Wilfried Lenauer on 18/10/2019 16:21:57: Am looking for a propeller 12x6 for Riot. When listing the spare parts of the company Max-Thrust .. he is listed as sold out. "Normal" 12x6 E do not fit. Who knows where to get these propellers? Thank you for info Hi Wilfried, Welcome to the forum! As you will read above I have translated your text using Google as English is the only language permitted on this forum, as per the Code of Conduct. Thanks for your understanding, I hope someone can answer your question Pete Quote Link to comment Share on other sites More sharing options...
Don Fry Posted October 18, 2019 Share Posted October 18, 2019 Why do they not fit Wilfried, Is the diameter of the motor shaft wrong? Or the thickness of the propellor wrong? Quote Link to comment Share on other sites More sharing options...
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