Billy Hell

My Feedback: (2)

OK, I have had almost no trouble with any of the plane but the wing still makes me nervous. As I add strips to the plans I realize I can no longer see a lot of stuff. The plans call for "a special tapered trailing edge " stick that is 1/4 by 1/4. I don't see this in my box and since the guy that I got the kit from seemed to take a lot of the other wood I will assume it's not there. Do I need this piece? The ribs are all cut at a 90 degree sland. Will a standard 1/4 x1/4 work? I'm stuck until I figure this out.

AtomHeartMother

Yes Billy, it is a shaped piece, but a 1/4 by a 1/4 stick would work just fine. Glue it to the trailing edge ribs and just sand it to match the contour of the ribs. Of course you want to leave the edge flat so you've got area for your hinges to glue into. Alot of kits just come with a stick you have to sand to shape. You could also find a pre shaped piece at a good hobby store, but that would be not worth the trouble. Sanding a piece to match would take 20 minutes tops. Just be careful sanding it. Those 1/16th ribs will snap easily if you bump them with a sanding block. Hope this helps.

Billy Hell

My Feedback: (2)

Thanks. I'm headed to the LHS at lunch today anyway so I'll just grab one.

PaulSwany

My Feedback: (45)

Most of the other Morris profiles I've built use the 1/4 trailing edge that has to be shapped on one side.... the 90 deg angle on the trailing edge of the rib sets one side of the 1/4" stick flush and parallel to the rib contour.... for the other side, use a long sanding block or a razor plane.. Just be carefull to keep it straight and don't sand on top of the ribs.... It's easy to gouge a rib or break one by accident... You can use a coupe strips of masking tape on the ribs to protect them from over sanding.

Alternately, you can shape the 1/4" trailing edge before you glue it on..... Good luck and take your time on this step....

Billy Hell

My Feedback: (2)

I have the bottom of the wing framed up and I have the ribs in place but not glued in yet. My question is I only see in the plans 1 piece of 1/8 x 1/4 behind the main spar for the hatch. What about the sides and back? It doesn't seem right.

Vref

My Feedback: (2)

if i know what you are asking, the back of the hatch has a tounge on it to hold it down under the trailing edge sheeting. the sides use scrap cap strips or other scrap 1/16th glued under the wing sheting to keep the hatch flush with the wing surface.

Billy Hell

My Feedback: (2)

Ok I get it. That means I can move forward. Wing by the morning!

Billy Hell

My Feedback: (2)

I don't know why the wing intimadated me but the bottom is all framed up and looking good. I read the next steps but don't see an image in the booklet. It says to cut 4 pieces of the cap strip. 1 on each side and 2 behind the hard wood piece that the hatch screws into. Is that right? I'll glue two of the cap strips behind the piece that the hatch will screw into? One on top of the other?

PaulSwany

My Feedback: (45)

Interesting... I wish I had my Pen Knife plans to look at.... I would think the only reason for the cap striping behind the hardwood piece would be for strength.... Seems like 1 piece would be enough.... Although I'd probably want to double up on the hardwood piece to make it a little thicker... at least in the area the screws go in.... 1/8 ply just aint got much bite....

Vref

My Feedback: (2)

my pk just has the 1/8th hard wood for the screws and cap strips on eithor side. the cap strips protrude about 1/8th of an inch, just enough to support the hatch. too much stuff overhanging your hatch will make an allready small radio compartment even smaller. my hatches are on top of the wing with the servos mounted to the bottom sheeting, for whatever that's worth.

AtomHeartMother

I built mine just as Vref described, Billy.
The 1/8th inch ply up front with 2 rails of capstrip material running perpendicular of the ply to form a box within a box. As Vref stated that's as far as you want to go because the radio access hole gets real small, real quick.
I put conventional servo rails in mine and mounted the servos to that, with holes cut in the hatches for the servo horns to clear. This method looks neater I think, but it's a big pain to do. Also another draw back is that my servo rails are glued in. Therefore if I ever need to get to my radio, battery, fuel tank or Rx, I have to cut out the rails and servos, and then reinstall. I like the servos built into the hatch idea, you just have be certain you've got a good solid mount for the hatch...and that the hatch has support for the servos.

Vref

My Feedback: (2)

easy profile radio installation
-make hatch in top of wing.
-glue 1/4 or 3/16 hardwood servo rails to bottom sheeting inside radio compartment. just a couple 3 inch long rails so the two servos in each bay can be mounted side by side, far enough apart for the servo arms to clear each other. inside servos elev and rud, outside servos ailerons.
-cut small 1/2" circular holes in bottom sheeting for the tops of servos to stick out.
-I use a micro throttle servo and usually put it wherever it fits in front of the others, my pk has the throttle servo taped to the center rib forward of the spar with the top of servo sticking out the bottom like the rest.
-stuff in the receiver and battery wherever it fits. preferably toward the rear and center for cg.
-good-to-go

AtomHeartMother

That's a pretty slick method for mounting Vref. I never thought of doing it quite that way.
I did forget to mention that I chose to put my hatches on the bottom of the wing of the Pen Knife, instead on the top, as the plans call for. I just wanted a cleaner look on top. So having the servos on the bottom, with the arms exiting thru the hatches presented a few problems. But I may redesign some new hatches with the servo rails mounted to them, similar to your method. That way I could get to my other equipment if need be. Thanks for the idea !

Billy Hell

My Feedback: (2)

That all sounds great. Thanks for the fast response. I'll be back at it tonight!

Ratchet

My Feedback: (1)

Atomheartmother ...

I just finished building a Penknife, and I put the hatches on the bottom of the wing. I was going to make the hatch covers out of 1/16 lite ply, and mount the servos as suggested by VRef. Should be plenty strong, and fairly easy to work with if you needed to remove the hatches for any reason.

-Ratchet.

AtomHeartMother

Yes, that was my plan...soon as I get around to it .
Been flying it too much to screw with it. But..alas the weather has turned again so I may get a chance.

Billy Hell

My Feedback: (2)

Mine is all framed up. It looks good. The wing is nice and snug. I'm going to leave the hatches on top. I'm afraid of putting my servos in a tray. Even a heavily reinforced hardwood one. Trays can come loose. I'll stick to the KISS method. Since this is my first kit one of those Ss really applies to me. The covering is next! I've never done that either.

Billy Hell

My Feedback: (2)

Emergency servo question! I have 4 HS 81s metal gears and one hs 85 metal gear. Some people are saying they wouldn't trust the the 81s and I'm sitting on 5 new ones. So should I try to get new 225 mgs? Will I even get enough throw on the 81s? Help!

jsonin

My Feedback: (4)

Well BH, I'd hesitate to put the 81s in the Pen Knife. The 225s are a great match seeing that you've got lots of surface area/force for the servo to contend with.... thus making the 81s a bit of a risk. I haven't tried using 81s on a Pen Knife - just 225s and standards... there is almost a 20 ounce difference in output between the 81s and 225s...

Heck, I'd give it a whack... he he.

-J

homeputer

I am just about done building a pk, I converted it to electric, I was also confused by the hatch thing , was lucky did what I thought the instructions said and it came out ok, I used one touge under on the top of the hatch's and then added a short pop stick under the bootom for screws to go into, and hold down the bottom of the hatch's, I am really ready to try this rig out, have to cover and setup radio yet, I used a 2:1 belt drive, shaft use's regular Prop's and a speed 500 motor, with 1100 mah 7 cell battery

Billy Hell

My Feedback: (2)

Here's a question. I was going through my hardware looking for screws for the landing gear. I found some fiberglass clothe that is obviously for the wing. The thing is this is a one piece wing. Why would it need to be glassed? I don't get it.

Balsageek

I wondered the same thing!!! I think it's to glass the wing to the fuselage. (put it in the corner btw the wing and fuse on both sides) That's the way it was on my sig fazer... I think I might leave it off of the pen knife.

Say, did you enlarge your control surfaces at all? I built mine stock and am wondering if their big enuf..

Later,
Matt

Billy Hell

My Feedback: (2)

No I didn't but I figured if that's something I feel like I need to do it would be easy enough to go back and do.

jsonin

My Feedback: (4)

I think the thin 1" wide glass sheet is for the middle of the wing??? I've forgotten... I may be mistaken..

If it's 1" wide, I'd thin CA the wing halves... I've completely forgotten if I did on my Pen Knives... whoops.

-Juhan

fast'n'low

My Feedback: (-1)

i left the glass out on my pen knife. It didnt say where to put it and it was not neccesary. By the way i dont know what my weight is but i used standard servos and my mvvs 28 hovers it at half throttle on a 10x3 apc. If you have any more questions email me since i dont check these forums much anymore. I remember thourougly how i built my pen knife which is still succesivly flying.