starry

hi guys got a problem with my extra maidened it week ago everything checcked and double checked all trims spot on center of gravity fine both ways got an os fs 61 max in her revved her up for take off bit of elevator it turned left rapidily had to give full right rudder in air about 2 feet turned to left flipped over and flew into bund on edge of runway took her home fixed the bit of damage a friend who is top flyer took it off next weekend and it done exactly the same any idea what causes this im puzzled all tail and wing lined up cant suss it help appreciated

Newc

Sounds like the ailerons are reversed.

starry

ailerons fine thats sorted in pre flights

parrthd

perhaps a problem in the engine thrust angle ?

bla bla

Your left wheel is stuck
Comma, full-stop, sentence?

starry

can the thrust angle be wrong on a artf its the recommended motor in it ahhhhhh i see i might have drilled and bolted the motor in on a angle yea kewl how do i check the line of that

parrthd

easy, take the cowl off and with a straight edge ( i use steel ) find a point on the engine that mirrors itse'f on both sides (usually the ledge that your bolts run through) now from thte back edge of that mounting rail measure STRAIGHT back to the firewall. both sides should be EXACTLY the same. this will put the engine 90 degrees to the firewall so all the thrust you have is whats built into the firewall. on the other side, with lases kits being more common, the chances of the thrust angle being off is remote BUT that is a possibility if you've already checked everything else.

starry

thanks i check tomorrow and keep ya posted thanx appreciate it parrthd

Newc

Another way to measure side thrust has just been published in Model Aviation and goes like this....Measure the distance from the tip of the prop - when the prop is horizontal - to a center point in the rear of the plane, such as the center of the fin at the base of the fin. The distances will be the same if there's zero side thrust. The numbers that are given to establish how much thrust there is are, if using a 12" prop there is one degree of side thrust for each 3/16" of difference in the measurements. I haven't checked the math.

Seems like a good way of checking to me.

By the way, while I realize that most folks do go through a pre-flight and that the ailerons are part of such an activity, I have also seen folks do the pre-flight from the front of the plane and tell me that everything is correct when they should have been at the rear of the plane and seen that the ailerons were reversed. It's a very common mistake that as an instructor I have had to correct on many occasions.

Dauntae

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Dauntae

Dauntae

One other thing that could be a problem is if the landing gear or wheels for that matter are not toe in, Causes all kind of ground handling issues, Make sure they are a little toe in to trak straight if they are pointed outward or one is straight and the other pionted in it can cause this problem when getting up to speed. OOPS I just noticed you said "in air" just ignore me now..... MY BAD

Dauntae

firstplaceaviator

My Feedback: (27)

Starry,
This sounds a lot like a stall and spin entry on take off. I wrecked a Lanier Laser 200 on the first few take offs. It was heavy and underpowered. After fixing it a couple of times, I finally made a successful take off. I just let it build up plenty of speed and let it fly off the runway. I was flying from grass and holding up elevator to keep the plane from flipping, I was inducing a snap roll on take off!

What kit is it?
What is the wing area?
How much does it weigh?

starry

hi havent checked thrust angle yet worked late but will its a seagull extra 300s 63.5 wingspan/765 sq inches wing area/wieght is 6-7 lbs 2.7-2.9 kgs the guys at the club have had extras and they say they had no probs with take off nearly straight up im really convinced that this thrust angle is to blame i sort that first and post ya the result and thanx guys for the great advice and i appreciate that some people do do things wrong when flight checks didnt mean to be off just answering the question no emotion in type ha ha thanx guys

parrthd

keep us posted, i'm interested in learning the source of you problem.

starry

hi all again checked the thrust angle measured from prop ends to a center point on fuselage and its turns out there is a difference of 25mm almost an inch measured the other way from a mirrored point on the engine to the firewalland there is a differance of 4 to 5 mm so by the time you get from that point to end of spinner there is a lateral differance of 25 mm the same will replace the engine mounts and get the engine spot on in line and hope this rectifys the prob will test her sunday morning post the results in the evening ok guys thanks for all ya guides and tip great to be a member of r/c with guys like you around takecare and again many thanks wait for the tears of sadness or joy ha ha ha

parrthd

thanking me is a nice thing but not needed. i'm glad i had to knowledge to help you out of a "situation" i'm also glad to see you've found (the most evident problem) the source of your misfortune.

can't wait to read about how she flies sunday.

starry

yeharrrrrrrrrrrrrrrrrrrr success thank you so much guys opened the throttle went up runway straight as an arrow tapped a bit of elevator finger shaking and she went up as easy as any plane ive ever flown handles like a dream and its arobatic capabilitys are awsome im a very happy bunny now great and thanks again drinks are on me when we meet up huh

starry

thats not me in pic but i love guiness thanx

parrthd

congrats, i have a 300S and it flies like a dream. it's one of my "keepers" i don't plan on that plane going anywhere anytime soon......

i'm glad you got the problem sorted out and hope you have many memorable hours of stick time with that bird. she will teach you a lot if you're willing to learn.

starry

im very willing to learn thanx mate ya bin a diamond on this one how ya doing with ya bipe plane you will enjoy flying it i fly a pitts special and its awsome got a 120 fs in her and its great gets a lot of people observing her fly as are club grounds are close to motorway service station and they stop for break from driving and watch take it easy and thanx

parrthd

[link=http://www.rcuniverse.com/forum/m_3561097/anchors_4576246/mpage_24/anchor/tm.htm#4576246]Skybolt thread[/link]

post # 586 is the most update that i've done....the bottom wing is now completed but i haven't roughed sanded it yet (still has LE and TE sheeting hanging out.) this isn't my post but another builder Mods-R-Me he was a great inspiration in my deciding which bipe to build.

richardshakan

I also have an ARF Seagull 300s. I noticed that the thrust angle is almost non-existent. I checked w/square & staight edge. Talked to LHS where i purchased it and they said to let them know what i find out online.

I'm Practically addicted to this hobby, being new to RC in general. I have been educating myself by going through the diff. forums on this site, and i must admit that there is plenty to learn.
So.... Can anyone recommend how much thrust angle is needed to get me in the air.

starry

if you built it from kit should be ok and thrust angles built into kit it was an error on my part i drilled and bolted the engine in on a skew so it had left thrust i just put some thrust wedges in on good instruction from the guys here on this site if ya bolted the engine in straight ya should be ok if ya all lined up ya should have fun with the extra flew mine 4 times today after trial yesterday and it awsome

parrthd

me too....me too!!!!! i got to fly mine today also........been around 3 weeks or so but she still cuts the air like the beaut she is.......