Hi Jonty - thanks for the reply - I have added a few comments to your narrative below. Cheers,
I don’t think you’ve ever really come across as overbearing etc James. You simply know your stuff and have years of experience to draw upon. The trouble with forums is reading people’s posts and looking at their photos but immediately knowing that what they’ve done with their model’s installation, set up etc is totally wrong. So, does the person who can see really problematic stuff get on the forum and politely (with the very best of intentions) tell whoever it might be that what they’ve done is wrong and that it could result in a poor performing or at the worst a damaged or smashed up expensive model?
The worst part is that the guy making the mistakes often will not (Publicly) take advice. This is why I write manuals, but despite this, as you have often seen, they don't look at the book and do what they think is right. All too often, they are not right but cannot admit it publicly
A good example is guys fitting out moulded glider wings with bottom hinged control surfaces, then using the control horns supplied with the model which are intended to be mounted with the horn above the top of the flap/aileron using a crossover linkage but with the horns UNDER the surfaces instead. Doing so is an instant recipe for disastrous flutter, as the pickup point is way too close to the hinge line, especially for the flaps. The thing is, the person then might say the horns supplied aren’t suitable. Huh? The simple fact is they weren’t meant to be installed that way and are therefore totally unsuitable and need replacing with horns with the pick up way further away from the hinge.
I have had that happen many, many times. Imagine spending all that money to buy an Alpenbrise and then either not having enough skill or perhaps being too keen to get the plane in the air by using exposed control rods underneath the wing instead of hiding inside it. I see it, I hate it, but I keep quiet.
Just how do you try and advise folks (with their best interests in mind) without them getting upset, pushing back and thinking (or calling) you a big headed know all?
I'm the designer, so normally they won't criticise me for my advice. They go deadly quiet and feel I have somehow wronged them. Possibly, again, the best idea is to approach them privately and ask if they would like the benefit of some experience. I think it's the public exposure they fear.
I’ll give an example. Six years ago I did a turn key job on a mate’s first mouldie, the name of which I’ll keep to myself. The cg was set midway between the advised figures at 78. On a nice lifty day it flew like a crock of you know what, it was literally rubbish!
It tip stalled at will, needed a huge amount of down for inverted, and rolled like a drunken sailor. Back at his place, I checked the rigging wing to tail. The V tail was nearly 3mm down at the l.e., so I raised the front tail mount tubes to get the rigging to 0-0. Having done that, nose weight was removed to cg around 90. Next day, away she went as good as gold, and more and more nose weight was removed flight after flight. It became absolutely fantastic… No more stalling, very little down needed inverted and the rolls were excellent. It stayed nicely in a dive and climbed like a homesick angel. Result!
So, where did the cg end up when checked on the rig? 97mm. I’ve since done the same work on another identical model which had been flown a lot, and the owner loves it. He says it’s a different model! I’m soon doing the same on another one.
Yes, but Jonty, remember—how many years of experience do you have to offer? Many years is the correct answer. That experience, coupled with a strong dose of common (Uncommon) sense and perhaps some intuition, cannot be taught and takes many years to come by. What is harder to do and much harder to explain to the buyer is to look at a model and know it has been designed incorrectly. Nine out of 10 people will not believe you—and yet it's around.
So, the thing is, a couple of years ago on RCG, a guy posted that his example of this model wouldn’t roll nicely, and posted a video of his plane in the air. It was totally stock, and I could see it flew like it… I posted (without going into the details) that a few set up changes would transform the model for the better, but he instantly took offence and said it was perfectly set up, he’d been flying for years etc etc. So, basically he told me to get lost. Nice!
There you go. That guy had spent his money in good faith and maybe even thought he had done a good job on the setup. And there you are a nasty, bad person, questioning his ability and, by default, his model choice.
Essentially the same goes for folks flying your designs. You might remember that over on RCG some years ago various folks were quoting the cog’s they were flying their Stormbirds at, complete with pics of how much up trim they needed to fly level, along with complaints of poor performance in light conditions, tip stalling etc. I posted my advice and the reasoning behind it. One guy asked you if what I’d been saying was kosher, to which you replied I was spot on in every respect. Thank you for that.
It was spot on, and you are welcome.
On this forum I’ve had it said to me that perhaps I should keep my opinions to myself from two folks regarding cog’s for your designs. It’s quite telling though that now one of them has gained more experience with cog’s for your wing planforms that his opinion is now apparently aligned with not only yours and mine but others around the world. What I just cannot get my head around tbh is folks flying both your designs and others waay nose heavy. So much performance in virtually every sense is left on the table, not to mention the increased chance of tip stalling.
Unfortunately, some guys don't realize the problem, Jonty. They think there is safety in lead - maybe they are used to soggy-flying models. Possibly, they fly foam models that are inherently hard to get to fly crisply. But one day, most people like that wake-up when they fly a correctly trimmed agile model that actually is safer than the nose-heavy variety, just as you say.
So, there we have it. The question is, do folks want to listen to well meant advice regarding how to properly put together models, balance them to fly at their best (not one of mine is an axe murderer nor the ones I put together for other people), and generally just getting ‘em going nicely, or what?
I think they do want to listen. Sometimes, I think they NEED to listen. If you give sage advice to someone with problems or publish a few tips and tricks to make the models easier to build and fly - especially mine - I will make sure I'm first to endorse as I have never seen you give bad or, for that matter, useless advice.
look at the model I spoke about. The manual’s cg range says 75 to 85. Ok, the tail incidence mod (takes an hour tops) is a game changer, but the ideal cg arrived at is 97. And that gives a really good flying model.
I know, it sounds unbelievable doesn’t it, but, it’s very true.
I have seen a model just like that. We called it "Density"...Wayne knows what I'm talking about
So, who wants advice from those who know, or shall the likes of Doc J go quietly into the night?
I think giving people the benefit of your hard-won experience is a bonus to all. Carry on, say I. As I said, I'll endorse you every time!
Very best,
Doc.
