Out of trim

[Peter Christy]

Posted by Trevor on 10/11/2018 11:45:02:

Of course the a lot of this trimming hassle would go away if we just took the springs off the sticks

Oooh! Don't get me started on that one! I was once approached by a gentleman to test fly his beautifully made Graupner Bell 212 helicopter (shows you how long ago this was!). He had been advised by Dave Nieman to remove the springs from the Tx, and had done so. I'd never flown like that before, but agreed to give it a trial hop and see what happened. It flew beautifully, and the trial hop became an extended flight complete with lazy figure-of-eights.

The owner of the heli was delighted, but it was only when I landed that I realised I'd been holding in nearly full tail rotor for the whole flight!!! If I'd had to turn sharply in that direction, I'd have been stuffed!

The problem with removing the springs is that it makes you oblivious to how near full throw you are just to keep it straight and level!

Thanks, but no thanks!

--

Pete

[Stuphedd]

Sorry if my last post was slightly OFF ! But in the days you were a novice , crashes were rarely your fault !! I tried to show that in my and my pals case a good 70% of crashes were due to poorly trimmed aircraft ,basically through ignorance .

And to John, no I have never tried to teach people to fly an "untrimmed " model ! BUT my son and his mate , to keep them on their toes have a reasonably stable model that they hand the TX over but switch it to mode 1 or 2 so the other has to swap his mind over , and they have yet to crash ! Now thats the ultimate in an untrimmed plane I think .

And my answer to the incidence meter , a must for all serious flyers , but on mine I use an app on the Iphone , lots of free ones and very accurate .

Back to trimming , I have had experience during this hot summer of one of those well known, expensive , foamy planes changing its trim due to the sun heating /warping the foam.( and whilst you fly, it cools down and the trim changes

The wing in the photo is a Dave Smith Excellsior

[john stones 1 - Moderator]

I think we learn to trim as we progress, through flying our own test flights and sorting models to our taste, test flights most important part is done in the workshop, teach that and the dramas get reduced.

[Dave Hess]

I used to train the newbs to fly in a very large club. They brought along all sorts of overweight and twisted aircraft with massive gaps in the control surfaces. The last thing We wanted was to discourage them by sending them home without seeing their plane in the air, so, as a general rule, if we could get the G-spot near enough, the engine pulled hard enough and the control surfaces moved in the right direction, they were going to see their plane fly, even if they weren't going to get a go themselves. I can only remember one plane that had a fault so bad that (G-spot IIRC) that I had to send him away with a plan on how to fix it.

I can remember one plane that turned to the left so much that I couldn't fly it straight with full right plus full right trim, so I had to fly it in left circles to get it back to the strip. In most cases, a moderate amount of trimming and arm adjustment got the planes flying well enough to be able to give the owner a shot. In the time I trained these guys, we never lost a plane.

Beginners have virtually no chance of figuring out how to trim a plane on their own. They can probably figure out to give a few clicks of up if the plane keeps going down, etc, but that's about it, bearing in mind that most of the time they'll be panicking enough to try and keep their plane in the air. You only get a feel for trim when you've flown loads of different planes in a variety of circumstances. I started with free-flight planes, so I had a good handle on trimming before I got anywhere near my first RC plane. I can remember hurling my Mini Super (1st RC plane) forward over the long grass without the engine running and without any transmitter input to check that it was properly trimmed before I ever fired it up. That's because I had been doing that with all my planes for many years.

I think that if I were going to a F3A competition, I might think about precise trimming with gauges and tests, but for normal club flying, as long as it flies more or less level when you let go of the sticks, you can compensate for everything else in the way you move the sticks.

In summary, if we're talking about beginners, the aim should to be to encourage them, to inform them and to help them make progress. First get their plane flying, then improve it where you can. I've been in a club where the emphasis was on preventing anybody flying unless their plane was perfect. I even had one of mine refused because the guy (safety officer) deemed my G-spot to be too far back, even though I'd been flying it for months when he wasn't there.

[john stones 1 - Moderator]

I agree Dave, beginners learn and listen, they bring their models out better prepared after the learning stage, just the same as we did, some beginners bring their first efforts out better prepared than some old hands.

[Don Fry]

I too am grounded in freeflight. When I started in radio I used to throw it for a test glide. But you run out of puff and strength when the motor gets to 40 size.

And I wish I had not read that post about taking the stick springs out. It's in my head, and making me queasy.

Edited By Don Fry on 10/11/2018 14:34:45

[stu knowles]

When the BMFA University Challenge event was held at Elvington, for a few years I was fortunate enough to be the STIG (stand in guy) pilot for a number of teams who turned up without a pilot. Most of the pilots, even the Team Pilots were presented with a variety of outlandish designed models, frequently very badly built and put together, structurally and aerodynamically unsound and of course for the most part...…. previously unflown.

In a Club environment the owner would be guided back to the car and advised to think again before any attempt was made to commit aviation but for these people it is fly now or their whole effort is wasted so everything gets its chance on the day. No test flights are allowed on the weekend of the event so the TX is handed over and the first flight is also the competition flight. Either max laps in the time, relaying tennis balls around the course or best of all, loaded up with up to 2kg of dead weight!

If you managed to get the thing in the air, the flight was completed with the sticks at all angles, There was no knowledgeable helper to put trims in for you. Frequently wings folded or moderately essential bits fell off or ceased to work but overall it was amazing to see just what could be persuaded to fly. By the time the second and third flights came around and having flown several other abominations in the meantime, you had forgotten the characteristics of that particular turkey so it was Groundhog Day yet again.

Win, loose or plummet it was a privilege to fly for these people and really 'character building ' for the pilot - and great fun.

My own test flights have never been a worry since

**LINK**

[Stuphedd]

Totally off thread again ,sorry! (I did get banned from Tesco but I wear a disguise now ).

I too was a stand in pilot for a University do , Like Stu said all unflown and untested , ist problem the TX , never seen one like that before , no switches had been programmed , no instructions , good start.!

Twin elec motors , going the same way , trike undercart , no steering ,! Did get it airborne , dropped the the sugar bag payload , , the harness that held the bag then got tangled around the tail plane , the servos on this 18LBS aircraft were 9gm !!

it had all been technically approved by the lecturers !!

Apparently the students were docked points for asking questions , so they didnt !

Like in the army Dont volunteer ! especially when you dont know what for !

cheers

[Geoff S]

stu, I love the phrase 'moderately essential bits' that sometimes fell off Can't honestly say I've experienced that particular tragedy personally - lots of other things but never that!

Geoff

[Geoff S]

I'm surprised the school in Ashbourne where Ian Redshaw is a technical assistant don't enter. With him advising the team they'd walk it! Especially with him as the pilot

Geoff

[stu knowles]

It is a fantastic competition that deserves to be supported much more widely - within education at all levels and by modellers. If you ever get the chance to get involved, jump at it! I enjoyed every minute

[SIMON CRAGG]

Posted by Pete Willbourn on 10/11/2018 12:00:16:

Sorry if my last post was slightly OFF ! But in the days you were a novice , crashes were rarely your fault !! I tried to show that in my and my pals case a good 70% of crashes were due to poorly trimmed aircraft ,basically through ignorance .

And to John, no I have never tried to teach people to fly an "untrimmed " model ! BUT my son and his mate , to keep them on their toes have a reasonably stable model that they hand the TX over but switch it to mode 1 or 2 so the other has to swap his mind over , and they have yet to crash ! Now thats the ultimate in an untrimmed plane I think .

And my answer to the incidence meter , a must for all serious flyers , but on mine I use an app on the Iphone , lots of free ones and very accurate .

Back to trimming , I have had experience during this hot summer of one of those well known, expensive , foamy planes changing its trim due to the sun heating /warping the foam.( and whilst you fly, it cools down and the trim changes

The wing in the photo is a Dave Smith Excellsior

I always check for wing twist (even with foamies), and its not often that both wings are 100% correct! IMHO a wing incidence meter is a must. Great idea to use the phone as well. Can you point me in the direction of the best app you have found please?

[Stuphedd]

The one shown in the photo

is Surface level

and the other I use is

Spirit Level

both free!!

[Dad_flyer]

After crashing my foam Bushmaster, I had little idea where 'straight' was for the re-build. The club member who took it up for me was excellent and got it from almost uncontrollable to a state where I could fly it.
Really hit home the need for trimming to be part of my progression from beginner.
The re-build had already made me reach for a balsa build so I know what shape it needs to be returned to if it comes home in pieces.