Ken Willard Schoolboy for Ponte 2023

[Wayne_H]

Very nice - should fly a treat

Test fly it at Ponty - since you've been assimulated into the MZ collective, the hive mind can assist, offer advice, laugh with you and celebrate your success

[leccyflyer]

No chance of a maiden flight for the Schoolboy in the wind and rain at Ponte Wayne, but the wing did go for a flight down the car park - plucked from the back of the car as soon as I opened the tailgate!

Did manage the maiden flight for the Schoolboy this morning, with calm conditions at the club field, so I went ahead with the plan to fly the wee model on rudder-elevator-throttle proportional radio. Checked everything out on the bench and it was going the right way, but the elevator control rod outer was moving and eating up much ofthe available down elevator. That was secured temporarily with a small piece of Blenderm tape and improved the situation.

The first attempted handlaunch went strongly to the left, but the long grass did it's job with a cushioned landing. Control surfaces checked again and they were pretty well centralised, so tried again with a bit more power on and got away okay. The model needed a bunch of right stick to go anything like straight and during the five minute flight, feeding in lots of right calmed things down a wee bit, but the Schoolboy resolutely refused to turn right - turned left with no issue, but even with full right trim still wouldn't turn right.

There were no really hairy moments, but approaching to land from the left was very challenging, every time I tried, I was lacking the ability to straighten out by putting in a matching right turn. Eventually I got it almost right, but settled for letting the Schoolboy come to a rest in the short rough, just outside the mown strip. A gentle landing with no damage.

So, a successful maiden flight, but not without issues. The elevator pushrod outer needs secured and I'm not convinced by the rudder authority with the tape hinges and after discussion have decided to whip those off and put some sewn hinges in their place. I'm hopeful that I'll be able to get the model at least able to turn in either direction.

On the plus side there is no shortage of power, with the 1106 motor and diddy wee prop, it sips at the available battery capacity and the model climbs convincingly away. In all the excitement I forgot to weigh the Schoolboy but will remedy that.

[Wayne_H]

Congrats!

Any landing you can walk away from......

[Tobe]

A few comments around Ken Willards designs in general...they were intended often for escapement which requires a slightly different technique both in trimming and flying.
I would always at least the smaller modell first trim them power off with some hand launches over tall soft grass exactly as he describes in his articles.
Normally to fly in our world they require more right trust and probably also some additional down trusts as we fly with more power, remember that Willard flew the SchoolBoy with a Cox Tee Dee .020 as his idea was to fly not on engine power but on the models characteristics, set the proper trust line can only be set if the modell flies properly in a glide.
The basic trim in the old days was a nice glide, left hand turn power on and right turn power off.
Often his elevators are on the large side and his rudders on the small side.
They fly better with the undercarriage on than off.
To get the CG I would consider to make a longer nose to avoid led or ballast and really be careful when building the tail section, i.e. keep it as lite as practical...
Overpower a Ken Willard design is often the best way to get the a bad flier out of it..
...last but not least is that they often would appreciate some more diedro, not much but a small add on could do the difference!

[leccyflyer]

Thanks guys - the model is a pretty little thing and I hope I'll be able to get it sorted out soon. This morning was perfect conditions for a maiden.

Tobe - the model has a very good turn to the left, but simply won't turn right. I'll give it some additional low angle test glides power off to see that the airframe is plumb - it looks okay to my eyes and I took a great deal of care jigging the tail surfaces to the fuselage. I was also careful to set the downthrust, which looks quite extreme to my eyes, but is as on the plan, but will add a couple of washers under the mount on the left hand side, to give even more right thrust.

Completely agree on the size of the rudder, which is very small - the model balanced perfectly with a 2s1p 800mah pack and I'm very pleased indeed with the power available.

[Tobe]

.....that's a typical sign of not enough right trust if the glide is straight forward.
....if you're fully satisfied with the power that means that you probably have maybe to much power!
Sounds like a paradox but....

[bluejets]

According to the original write up I have here, he did indeed use a cox .020 first up but then replaced it with an .010 as was originally intended.

Apparently flight was much more appropriate.

https://www.rcgroups.com/forums/showpos ... unt=3742

[leccyflyer]

That's what I'd read in the original article - the prototype flew with an .020 then Ken swapped to an .010 and liked the flying characteristics better.

I've now weighhed the model - around 9 oz =258g with a 2s1p 600mah pack. The wee 1106 motor is pulling 6 amps on that battery with the 2x2.5" prop, at WOT. That equates to 55w or 98w/lb at full throttle, which is more than enough power. So Tobe has a point - the SChholboy is rather overpowered with that tiny motor - that's what the throttle stick is for though. I couldn't believe how much waft such a tiny motor generates. No need at all for Plan B, which was to fit the larger 1306 motor in a dummy .020 engine mount.

[Shaun]

At this rate you'll have around 15 aircraft for next year.

Don't stop bashing the balsa.