Need Advice
Hi all, I have a Roban Bell 407 700 size just recently completed. I'm running...
Tony F.Hi all, I have a Roban Bell 407 700 size just recently completed. I'm running 12 degrees positive pitch and about 3 degrees negative. This seems fine on all my other scale ships but this one seems to not want to rise sort of speak. If I'm hovering stationary and go full collective the model goes up very very slowly. I'm afraid to fly it thinking it may sink to the ground when I come back to a hover. Any advice would be great.
Thanks!
14 Answers
Try bumping up the head speed and adding 1 degree more positive. Reduce the negative by 1 degree so your overall range stays the same. Test the climb rate again and add 100 RPM in subsequent tests assuming you are not over-speeding the manufacturer’s recommended speeds. The disc is simply not generating enough lift to overcome the weight of the aircraft so that the problem you are trying to solve.
I don’t use a scale set up on my Hughes MD500E scale 600 size 11deg positive and 11deg negative. Head speed around 18-1900 . Michael is right on the head speed that will be the first thing to try keep increasing it and see if that starts to work and higher to where you are comfortable with.
Thank you, I will make some adjustments and retry. I can’t remember the head speed but I think it was under 1400. I’ll report back.
Tony
verify head speed. The 700/800 size Roban should be around 1200-1300 I would not recommend anything over 1300. -3 and positive 12 is right on the money. What is the pitch at mid stick? Also what FBL are you running? Are you running a pitch curve?
I'm running a microbeast. Motor is a Pyro 750-56 and a Kosmik 160 on 12s. I will go though and check the whole pitch range again. Pitch curve linier.
Thanks for weighing in Tyler!
Tony, I take it you are flying a 4 blade head right?
Buddy, not to contradict anyone, but I also fly a 700 size 407 4 blade head at 1300 positive 12 neg 3 and 5.5 midstick hover. I have been flying it since 2015 and it flies absolutely great. You may want to check where your stick position is for hover, then look at your curve. To Michael's point, if you are flying a turbine at 55 pounds, he is also right... Just my 2 cents.
Richard, yes, this is a stock 407 kit, the green one. No special pitch curve just a linear curve. I had the Mercy Air Bell 222 and it was fine. I must be missing something. Just have to go back and recheck everything.
Also check how is your Batteries wired if you are using two 6s batteries. Sounds like you have more experience than me on scale builds.
Finally got a minute to check things out. Not really sure what happened but was only getting 10 degrees at the top. Il bring my tach next time and verify head speed. Thanks again.
Let us know what you find out on the head speed.
Tony, just following up with you. Did you find out what was going on?
Hi Richard, actually I’m taking it out tomorrow. Weather here has been crap. I’ll post up afterwards.
Thanks, Tony
So, we were out this morning. I had a friend use my optical tachometer to check the head speed. 1100,1300,1400 +/- a few RPM. petty much where I set it up. It felt best at 1400 and better then the first few flights. Good enough to fly it around. Nice and smooth too. At 1300 she just won't climb to where I feel comfortable. I'd say that's as good as its going to get. One note, I'm also running a set of scale 700mm Spin Blades.
Thanks for all the advice, Tony