pmcderm993

I've just finished my Pen Knife. I have an O.S. 32 SX on it. Balanced exactly as on plans. Weight is 3.5 pounds. The recommended throws are in degrees on the plans. What should the low and high rate throws be in inches? Seeing the huge control surfaces and the amount of throw capable has got me scared. I would like a mild first flight (low rates) and will work up from there.

I am using an 8 channel Futaba radio. What other programming tips can anyone offer--mixing, exponential, etc?

Since winter will be here soon in Minnesota, has anyone flown this plane with skis? Does it fly much differently with skis? I have a pair of nice aluminum skis on hand.

Thanks

PaulSwany

My Feedback: (45)

I'd definately start out on low rates.... I have a plane this size and it's pretty twitchy compaired to my .40 size birds...... I'd put at least 30% expo on all control surfaces... You might try playing with elevator / flap mixing later..... I'd go easy on the high rates until your comfortable with the plane.... work your way up from there.

BuddyB

I flew my Pen Knike for about 2 yrs.It is a great flying plane.I added
2 wing ribs when I built mine.I had a.28 Bluebird engine with a 10X4
prop to keep the speed down.I coupled aielons and elev.for slow
landing speeds,it could be landed at less that 5mph. I am sorry I sold
mine and I am looking to buy another kit. I have built and flown more
that 13 profile fun fly planes and this one was one of the best.
[email protected]

PaulSwany

My Feedback: (45)

Buddy - What was your finished wing span? I have a set of plans for one of these in the garage.... I'm going to have to build one..

pmcderm993

Well, I guessed at the angles and went flying. I did put -30% exponential on all surfaces.

First flight: Scarey--too twitchy even on low rates. Needed lots of trim, mostly down trim, but it doesn't look like it on the ground. I landed it somewhat fast.

I lowered my low rates and put my high rates where my lows were.

2nd flight: Gave up on trying to take off of the paved runway due to ground looping. No problems taking off from the grass. Loops were tight and rolls were quick but not extreme. Turns were very uncoordinated, but I was afraid to use the rudder since it is so strong. Tried the flapperon mixing at 50%--tighter loops, but not extreme. Dead sticked, too lean for cold weather. Landing was smooth, slow and uneventful.

Mixed in 20% rudder with the ailerons. Lowered my low rates a little more.

3rd flight: Much better turns. Plane flies just above idle. Inverted flight was difficult, plane looped with any down elevator. Knife edge power is very good. It would knife edge loop by accident. However, I don't know why it pulls toward me so much in knife edge. Landed very slowly, touching the tail down first.

Took out some of the down elevator travel, but have not tested it.

First impressions: This thing seems way overpowered. Maybe I just need to get used to it. Normally I like as much excess power as I can get. I need to figure out inverted flight--no or little down elevator? How little down elevator? Need to figure out knife edge coupling. It really pulls toward me. I kind of wish that I had put on a steerable tail wheel.