I am building a couple more at 17" span.. one is for me and one for my FB..this time using 9mm EPP and leaving the KF step off the build..
I wanted to check the difference if any between having a KF step and having no step for the models performance..

the build is easier to start with, no KF lamination means less glue and less foam used..
I got two 17" models from one sheet of EPP..580mm x 900mm.. at just under £8/sheet when delivery is included

to get the COG when you don't use a KF step layer , it requires the gear to go more forward.. the step layer previously added weight at the front...
note COG on the 17 is at same location of 5" back from the root leading edge
note 2 ,,this is a forward starting safe COG, a bit nose heavy...

build pics

The basic build always follows much the same pattern..

Part cut down the centre line on the wing, fold down and hold at 20 degrees while the crack opened up is filled with cool melt glue..

Fit the strapping across the wing above and below.. UHU por

Cut, laminate and fit the spline.. don't forget the angle of down thrust cut at the front.. UHU por

Cut the elevons out, chamfer and refit hinged.. UHU por

Add the tip fins, cut and trim the front to a slope.. top and bottom.. UHU por

Now add a bead of hot(cool melt) glue to all the main joints, along the spline, fins and nose block.

The CF rod fin support is fitted first, then the fin trimmed to fit the rod.. the rudder is hinged with UHU por

The bare airframes weigh 2.2-2.3oz

motor mounting.. cut a 1/16th ply plate triangle to fit the front block..
fit the motor mount to the plate.. use small self tapping screws, first fit them , then remove them and use CA in the now threaded ply to reinforce the holes.. when the CA is dry refit the mount and press into the nose block .. use cool melt to fix the unit to the bock..
The nose block is slotted to allow the wires to go back to the esc.

The wheels are on a made up using CF 3mm rods as legs... tied in an X shape with an axel across the bottom of the X.. make sure there is enough clearance for the prop to miss the ground when the model is held level..
First l bind the X then arrange it to fit on the front triangle.. add thin CA to the binding to fix the shape.. make two ply plates to suit the nose block sides.. place the legs on the ply to get them in a position that will allow the axel to be in a line with the front wing edge, and mark up where the legs are to go.. drill small holes either side of those leg positions and with multiple loops, sew on the legs to the ply.. fix the threads with CA.. attach the axel and wheels.. see pic4 in post 248

here I am going to try a 2211-1700 from hobbyking

Dave......What a difference a little more downthrust makes!

I put a couple of thin washers on the top screws between the firewall and the motor after watching how it was flying. It can not be much more downthrust, but what a huge difference in the way it flys! It wants to stay level under full power as well as glide which is what wanted. I got to give it a go last Sunday. Ran four batteries through it and it is a much more predictable, better flying airplane. It will probably be one of my favorites after more flights and me getting accustomed to it and have more confidence in my flying.

My wife shot some video of the first flight after the adjustment. I put together a small video (actually too long ) of the uncut video. I just wanted you to see how your airplane flys in the Florida air!

It has been several years since I had a Nutball, but the PP1 kind of reminds me of it. The PP1 seems more predictable, but also needs more full time flying.

Thanks Dave for the great design. I know you have put a bunch of work into getting it tested and improved.

The video seems a little jerky, but it does show how the PP1 flys for me. YMMV

(5 min 29 sec)

Originally Posted by High Flyin'

Dave......What a difference a little more downthrust makes!

I put a couple of thin washers on the top screws between the firewall and the motor after watching how it was flying. It can not be much more downthrust, but what a huge difference in the way it flys! It wants to stay level under full power as well as glide which is what wanted. I got to give it a go last Sunday. Ran four batteries through it and it is a much more predictable, better flying airplane. It will probably be one of my favorites after more flights and me getting accustomed to it and have more confidence in my flying.

My wife shot some video of the first flight after the adjustment. I put together a small video (actually too long ) of the uncut video. I just wanted you to see how your airplane flys in the Florida air!

It has been several years since I had a Nutball, but the PP1 kind of reminds me of it. The PP1 seems more predictable, but also needs more full time flying.

Thanks Dave for the great design. I know you have put a bunch of work into getting it tested and improved.

The video seems a little jerky, but it does show how the PP1 flys for me. YMMV

Nice flight Ray. Very impressed with the results of the adjustment.

Pat in Oz

going well ... and looking at the video the model is set up for fast flight and windier conditions just nice... flying faster you do need to keep full control, just like any model


now you need to get your COG positions better sorted, so you can adjust the battery position for slower flight, and for different wind conditions ... doing that will open up the slow flight envelope..
trim to fly at just over half power....go inverted.. if you have to push down much to keep level, its too nose heavy, so a bit at a time move the COG back and re-trim... the loops will tighten, the rolls will get more axial.. and inverted will get easier..
Also try to fly it slower, go for a half power or less cruise and trim for that..
Landings will also get slower, the nose can be easily held up on the approach , balancing that high nose with more throttle , and the model plopped down right at your feet...

My flying now is always slower, sedately at low to mid power, with bursts to do rolls or loops, and good use of throttle makes these capable of some crazy moves..
flying at full speed they are much like any sport model.... I was always flying at full power when I started many years ago, and it took a long while to realise that going slower makes it all a lot easier.... I was a bank and yank full speed flier for too long....lol

once these things are trimmed they will fly hands off... just needing throttle variations to adjust the height.. you can trim the rudder to produce slow turns and they will go round and round, with the throttle making it climb a bit it will go like a free flight, round and round and up and up.. and away...lol

The nutballs are very much the same to fly, their best performance is at never max speeds,

My new one without KF is all done, it just needs velcro for the battery tie down and then the control rates programmed in..
My FB has his one and with some luck might have it ready for this Thursdays evening session

then some weights worked out

The previous KFm2 -17" weighed 6.4 oz with its 17gm hyperion and a 500 2s .. 3x 4.3 servos and the same prop, rx and esc

The new 9mm non KF has an AUW 6.25oz....
the motor is a bigger 2211-1700 (red and black)from hobbyking, the servos are 3x tgy-1440a, with a 10A esc , 4gm RX and an 8x4.3 prop.....
3.7ozsqft

which all feels very promising for this Thursdays indoor session.....

Hi Dave,I have finally started on mine.Had some leftover dollar tree foam to use up so I thought I'd give it a go.I cut out a 19 inch version.I have been thinking all along this used elevons.Now I read more carefully and see they are ailerons.

Have any of the builds used elevons?Just wondering.Thanks for all your work.

They are elevons. There is no separate elevator, only elevons and rudder.

That makes sense.Kind of threw me off with the rudder.Never had a elevon plane with a working rudder yet

The rudder is an essential for when you fly it slowly... it makes for nice and easy turns.. with no rudder its a faster bank and yank model , it can be flown like that but its much better with both...
The rudder will double the roll rate, and steer it when you get the nose up and go at slow speed..

The testing indoor last night showed to me that the KF step layer is not needed for improving the flight performance... Being critical I could not see any loss of performance.....

I had been wondering just how effective the KF was on these sort of shapes.. does it improve performance or not... it seems not.... but it does strengthen the wing....

The new 17 (no KF) flew beautifully and the power setup is improved yet again..
Power now is using the 2211-1700kv from hobbyking with an 8x4.3gws prop.. Its quiet and there is loads of power for hover and vertical acceleration.. Its also gives very good flight times, as the model will fly nice and easy on less than half throttle...

However when using a single layer (no KF) it is definitely more prone to impact damages.... The multi layer KF prevents the foam tearing...
It got torn on the front corner and the motor block is also coming apart, the ply mount also snapped...
Its a 10 minute job to repair it .. a thicker bit of ply will help spread the front impacts, and I think I will also add some pallet strapping round the leading edge to prevent future damages...

Note on COG.. without the doubled front layer the gear needs some rearranging to get the COG to the correct spot... on the 17" the COG safe starting spot is 5" back from the straight front edge... note this is nose heavy , but it does fly very stable when trimmed like that
Note on thrust angles... only 5 degrees down and 2 right used on the single layer wing and that is fine...

also noted... my FB as usual got his setups a bit wrong... On the one I made for him, and despite me asking about his COG it was actually set 1" behind the spot, he was wondering what was up , why it kept pitching up... why it was pitch sensitive... lol..
despite being way too far back it would fly.. just not being easy for the pilot.. lol
On his own build , a 17" 6mm depron KF version, it was pretty much the same...the wrong COG plus he didn't use any down thrust... again he makes it hard for himself, it ended up with a load of down elevator trim but it still flew...

the same evening I was also trying my 26" slofly 3D model ,found on this thread.. https://www.rcgroups.com/forums/show...59721&page=167
the slofly is very neutral in flight, no stability and its highly responsive... and that's an understatement..
It made me realise what an easy fly the PP1 really is...

Hi all, I have a HK 10g outrunner and a 7x5 prop. I have a Turnigy 6 amp ESC. Nano-tech 2 cell 25c 180 mah lipos. I do also have a 10 amp ESC and Zippy 3 cell 20c 1300 mah. Any thoughts on what WS i should go with and also best lipo/esc combo for the PP1. Would like to fly primarily indoors in a small sports hall.
Thanks.