Qwerty's Thread from "Fly it on or Stall it on...?"

[Guest Qwerty]

So Querty, what did you do to the Jab ?? praytell.......................................

 

I got me water bottle, packet of mints, and.... a stump to sit on...

 

Yes,we won't tell anyone.

OK.... I was dissatisfied with the roll response of my SP6. It was so bad that at full throttle on steep climb out it needed almost full aileron deflection to maintain wings level against the torque roll from the engine. Also, in what I like to refer to as moderate xwind landings (up to about 15 kn and gusty) I could not maintain wings level with the ailerons alone, I also frequently needed to give it what little rudder it had. I've reported on here before about the lack of forward stick available, again, in this case not enough to counter the pitch up from the 6 on full noise. Also, the aircraft will not even get close to the stall with power off, it needed more than a healthy dose of power to force it to stall. In this configuration it needed plenty of right aileron to keep the wings level with the strange result that when it did stall, it suddenly stalled the right wing giving a very convincing entry in to some sort of snap roll to the right....very interesting. last but not least, the rudder, the rudder deflection was about 5 degrees and simply not effective. The lack of rudder authority is responsible of the previous owner putting it through a fence and for me getting an uncommanded runway excursion.

 

After much research and cogitation I decided to fit a set of J120 ailerons which are about 250 mm (27%) longer than standard. I also intend to increase the maximum aileron deflection to give me a fighting chance at controlling the little turd. This involves taking the wings off and cutting bits out of them. While I have the aircraft in bits, I have also increased the maximum elevator deflections by about 15 - 20% and I have almost doubled the maximum rudder deflections.

 

A mate painted it for me yesterday but unfortunately I gave him the wrong paint colour. The aeroplane needs painting, reassembly, adjustment of the aileron maximum deflections and its ready to go.

 

I am expecting it to behave a whole lot better when I want it to do something. I'm looking forward to flying my "new" SP6

 

 

[slartibartfast]

What about the rudder Qwerty? I expect you'll run out of that even faster now.

 

Try taping some cardboard to it. Make sure you do it before the repaint. Otherwise it might look silly.

 

 

[Guest Qwerty]

......... and I have almost doubled the maximum rudder deflections.........

 

What about the rudder Qwerty? I expect you'll run out of that even faster now.

Try taping some cardboard to it. Make sure you do it before the repaint. Otherwise it might look silly.

What????

 

 

[slartibartfast]

Oops. I missed that bit.

 

It will be interesting to see how it goes.

 

 

[Guest Maj Millard]

So we are looking at good planned modifications, Vs bad unplanned modifications ?. I would imagine you may have two areas that you may want to watch, when you get flying again. The additional aileron deflections may cause some adverse yaw, but you should now have the rudder authority to handle that. Also watch that the additional aileron area and throw, doesn't have the effect of stalling the outer wing, resulting in a severe drop. Also because of the additional rudder authority, watch it on landing, as too much rudder can get you into trouble also on a taildragger. I would suggest using and exploring your 'new' control authorities easy at first, and maybe explore them with some recovery altitude below you.

 

Should be interesting, let us know how things go.

 

Now the next obvious question would be, why has the Jab factory let a machine out that by your accounts has such exagerated, and I would imagine potentially dangerous flight characteristics, or is you machine an odd bod ?? IE: shouldn't have the six in it ?.

 

Your honesty in explaining the situation is appreciated.........................................

 

 

[Guest Qwerty]

Maj,

 

I intend to re-rig the aileron throw (today actually) to give more up (aileron) than down to minimize the addition of adverse yaw. They are already rigged that way but slightly more will/should be better.

 

I'm not worried about the rudder authority/sensitivity. The blasted thing practically didn't work before. I woud kill for too much rudder, at least I could de-tune that without too much trouble. I intend to do some careful upper air trials. The strip I'm working from is not what you would call ideal for ground handeling tests. I have tons of tail wheel time and the Lightwing (most of my time) is not under ruddered by any means. A while ago, I fitted stiffer springs to the tail wheel which gave me RESPONSIVE ground handaling, it might even be a bit too sensitive but I'm used to it now and it works well.

 

I can understand how the thing came to be. I can fully understand pilots asking for this configuration and I can understand Rod going along with it. It just (IMHO) didn't get enough (if any) development work. The concept is excellent, it just needs to be made to work properly, It is so close to being a ball-tearer of an aircraft. It is impressive to fly now but not a good thing for low time or tentative pilots, this thing really is a bit hairy chested and it will kick you fast and hard if you are not on top of it. I don't expect my mods to tame it but I hope at least when you give it some aileron and rudder it will respond.

 

I'll let you know how it goes, with any luck I should be able to report tonight. Today I have to bolt it toghther, fabricate the bits to alter the aileron throw and differential, re-rig the flaps and ailerons (with reflex thanks to one of the Maj's posts) and she is ready to go.

 

I should give a big acknowledgement and thanks to obad for his help, advice and his expetise with FRP.

 

Cheers, Qwerty

 

 

[skeptic36]

Hi Querty,

 

When you make all these mods do you have to change the registration category of the aircraft or are there some things you can do without having to do that?

 

Regards Bill

 

 

[Guest Maj Millard]

Sounds good Querty, On reflex, it is basically on of the few free rides in aircraft design. Reflex on flaps definetly works (a free six knots on the GA lightwing). On my GR I had the ailerons up a fair way at one point, probabily 1/2 to 3/4 of an inch above the streamlined position,(wingtip), but then after a few hours, I ended up dropping them back a bit, as she started to drop out on me, just in the flare. I was loseing just a bit of wing lift there on landing. I often land fairly heavy with tool boxes etc. I guess I reached the upper limit, and came back a bit. They are still up maybe 1/2 " and all is good again. It sure does help up the cruise speed a bit, which certainly pays for itself over a years flying. Basically what reflex does I believe, is reduce the down-air off the rear of the wing, and therefore reduces the drag over a large area of the wing, or the whole wing if you've got it on flaps too................Maj

 

 

[Guest Qwerty]

The Jab is back in the air. The aerodynamic work included 27% increase in aileron area with 36% increase in deflection. Reflex flaps and ailerons by about 3deg. Increase rudder deflection by 75%. Increase elevator deflection by 20%.

 

The results are excellent. The roll rate has improved dramatically, Rudder authority is exceptional and the elevator is nicely responsive. It looks like I have gained about 3 or 4 kn by reflexing the flaps and ailerons. It is now a pretty well balanced aircraft. The only down side is the increased pressure required to operate the aileron but I am sure that I will get used to that. Obad and I rigged it by eye this morning and it is trimmed perfectly, I won't be making any adjustments to the trim, it flies S&L hands off. I have only done about 10 min and two landings in it so far but I am very pleased with the result. All this in less than a week thanks mainly to Obad.

 

Septic, The a/c is a 19 reg, I am an L2 and I informed Steve Bell prior to undertaking the work.

 

One happy Qwerty :thumb_up:

 

 

[skeptic36]

Septic, The a/c is a 19 reg, I am an L2 and I informed Steve Bell prior to undertaking the work.

One happy Qwerty :thumb_up:

Yeah, thanks for that sQwerty ;), glad it all came together nicely for you.

Regards Bill

 

 

[Guest Maj Millard]

Good job Querty !!................................................................

 

 

[Guest Qwerty]

Thanks Maj.

 

BTW Qwerty is spelled Qw.... not Qu....

 

Cheers, Qwerty

 

 

[Tomo]

TW Qwerty is spelled Qw.... not Qu....

And the reason is because he couldn't think of anything else... and so he just started at Q an tracked 090 for Y. ;)

 

 

[turboplanner]

I know the secret - his ancestors were typewriters.

 

 

[Guest Qwerty]

And the reason is because he couldn't think of anything else... and so he just started at Q an tracked 090 for Y. ;)

My real name is Quentin Winston Erty the 8th. the first two initials and my surname makes Qwerty.:hittinghead:.

 

Turbo is partly correct about my ancestory, my great great great great great great great great grandfather Quentin Winston Erty the 1st invented the typewriter and showed his sense of humor in the layout of the keyboard.

 

BTW for historical accuracy, his wife's name (my great great great great great great great great grandmother) who was of welsh descent was Asdfg Hjkl. Their second child, a daughter was Zxcv Bnm Erty. and finally his dog's name was Uiop.

 

So now you all know my family tree.

 

Qwerty:thumb_up:

 

 

[turboplanner]

Their first child, I take it, was the black key of the family, and had been struck off?

 

 

[Guest Cloudsuck]

OK.... The lack of rudder authority is responsible of the previous owner putting it through a fence.

OBJECTION YOUR HONOUR! The previous owner (Me) didn't put it through the fence. He toe'd the brakes in time to stop it going through the fence and stood it on it's nose bowl :)

 

All three owners of this aircraft have now had runway excursions. The aircraft is great at speed but is a pig at slow speed. I think that the aileron mods by Qwerty will be great and will make the wing exactly the same as the J120 (Obviously Jabiru identified the small aileron problem as well but too late for the SP).

 

This is a similar aircraft to that ground looped by Middo in a big x-wind at Natfly a couple of years ago except Middo's plane had a tiny little rudder. The vertical stab surface area was greater than the rudder surface area.

 

Qwerty's rudder has a much larger surface area and greater ratio to vertical stabilizer surface area so maybe a couple of more degrees of deflection will do the trick.

 

Good luck Qwerty.

 

 

[Guest Qwerty]

OBJECTION YOUR HONOUR!

Withdrawn.

 

I thought you said that you put it through a fence....or did you say the first guy did?? It wasn't a pig...if you poke a pig it responds. I am too busy right now to test fly it..I am itching to get in it and see what its like. The rudder works really well. I didn't say before but I adjusted the brakes. Because of the forward-aft pivot points for the left and right peddles, the toe brake geometrys needs to be DIFFERENT to get them in the same place and get the same feel.

 

BTW its all the same colour now too. It looks shmick. Come down and bring Grummo with you with her sister ship. You will both be plesantly surprised with her.

 

Turbo,

 

The first son was Quentin Winston Erty the 2nd, The second son was @#$%^&*()^ and emigrated to sweden and noone ever heard from him again.

 

David,

 

Your information is wrong, I know what you David's are like....trying to take over the world. I know that no David will rest untill everyone is David....well I just won't cave in to the World Wide David Domination of the World movement. My name is Qwerty and I'm not going to change it.

 

Qwerty.

 

 

[turboplanner]

Cut the ho ho or he'll be looking for the contract to deliver Christmas presents for next year...........

 

 

[Tomo]

Cut the ho ho or he'll be looking for the contract to deliver Christmas presents for next year...........

I was more thinking along the lines of going into Gardening ;)

 

 

[Guest Qwerty]

After a short test flight program this morning I can report the following.

 

With no flap the aircraft gets mushy and horrible at about 55kn, I didn't bother going any slower.

 

With full flap it now gives a propper stall with a propper nose drop at 42 - 43 kn with the stall warning going off (comming on I suppose) at about 46 - 47 kn. It used to slow to only just below 50kn and then just mush along, this is a far nicer setup.

 

Adverse yaw is still horrid without the application of rudder but then who cares.

 

It side slips really well, I forgot to side slip till my last landing and I didn't give it a fair trial but I got plenty without going anywhere near the stops.

 

I have landed it three times in the new configuration and the landing attitude and AOA are a lot better (steeper). I flew it right into the stall warning and it was blaring nicely when the tail wheel touched down.

 

Qwerty is one happy camper

 

 

[slartibartfast]

Congrats Qwavid. That's a great result.

 

 

[Guest Qwerty]

Cficare

 

No but it does stick out a bit when you are up mucking about with roll response, it happened, I reported it.

 

:thumb_up:

 

 

[Guest Cloudsuck]

Is the roll rate any better at 55 kts?

 

 

[Guest Qwerty]

Slow is where the greatest improvement is in roll. It is a different aircraft it is a lot more comfortable to use now. Grummo's was good but I think mine is better....maybe....its hard to remember exactly what Grummo's was like. Come and have a fly!! Better yet, fly it at Temora.