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Sep 07, 2019, 08:08 AM
Tyro of the Hudson
We have one like that in the area, a Pt21 or 22 and a BT15. The other folks called it a BT10 but anything I see online calls it a BT15.

Also had a 3/4 scale Eindecker flying that day. Experimental category with a Rotax snowmobile engine.
Last edited by SteelonSteel; Sep 07, 2019 at 08:21 AM.
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Sep 15, 2019, 03:33 PM
Registered User
Dave#13's Avatar

Grass ?


Hi all,
Thinking of getting one of these.


What size are the main wheels?


How does it handle a rough grass runway?


Do the new ones have more weight at the front - I saw a post saying the dummy engine weighed much more and wonder if they added something inside?
If so, does it cure the CG problems mentioned?




Thanks all


Dave.
Sep 16, 2019, 09:55 AM
Registered User
mdmyers's Avatar
Mains are about 2.7" diam. I usually fly off of a gravel track but have done a soccer pitch as well and it will fly and land there but have to manage the elevator to not nose over. If it was too deep or rough I could see it being trickier. I have one of the originals so can't speak to current production but base on the posts here it does appear that weight has been added to the engine at the factory now. I fixed mine originally by adding weight but later went back and corrected a decalage issue and removed the weight.
Sep 16, 2019, 10:18 AM
Fire Marshall Bill
The original dummy radial was hollow. Now it comes as a solid piece with all the cylinders filled and plugged. Weighs several times more the the original. This seems to have compensated for the problem, but the real issue seems to be the decalage angle.
Manicured grass will work, but if deep and full of holes, not so much. Nose overs are not a big issue though is you land it slow motor off.
Sep 17, 2019, 02:29 AM
Registered User
Dave#13's Avatar
Thanks for your input guys. That helps!
Sep 26, 2019, 03:46 PM
Registered User
Creative RC's Avatar
Made it even more streamlined. This conversion is lots of fun and very easy on grass.
Oct 05, 2019, 01:45 PM
Tyro of the Hudson
Still get some rollovers but not like before. I moved my 2200 battery back to hang off the battery tray. My battery is far enough back the front strap misses the battery.

Last flop over was all my fault, a plopped landing.

Not sure what the heck I was doing before, measuring CC on the bottom wing? Flying with the battery at least an inch farther back now. It has been weeks since I flew it.

Getting closer though.
Oct 16, 2019, 04:35 PM
Registered User
Dave#13's Avatar

Roll overs


Hi all,


I've just got one of the new ones and had about a dozen very successful flights but only three good landings!
The field I fly from is grass, cut but a little bumpy.


Take offs are fine and the model handles the grass strip OK.


The problem I'm having is that the model comes in to land fairly level but digs in and does a roll over.


I have removed the dummy engine as I read in a post that it is heavier than the early models.


It's nine ounces! Each cylinder is filled with steel !



My CG is a little forward (I like to fly slightly nose heavy) but with the dummy engine off it still balances within the recommended range.


Next time out I'll try a flight with the dummy engine off to see if I can get better landings and still fly her OK.


My question is - does anyone know how the dummy engine comes apart.


I can see that it is moulded in two halves but I'm not sure if its glued together or has clips moulded into each half..

Can anyone help, as I'd like to try removing some or all of the weight without breaking the engine as it looks really good?


Thanks


Dave.
Oct 18, 2019, 08:30 AM
Tyro of the Hudson
I agree, they went overboard with the weight. I don’t see how you could cleanly break her in two and remove half the cylinder weights.


My band aid approach is to move the battery far back like I posted above. Mine is the v2 heavy engine too. I cracked my rudder last trip out due to the flip over effect. I am going to repair with thin CA and I will stab sharpened servo rod segememts vertically down the rudder inside for reinforcement. One of my main gear strut decorative hinges broke as well. Not sure how that happened. Simply too stiff I think.

The plane is too heavy in v2. With the battery nearly half off the battery tray it flies well. I need more time to evaluate more fully. My first two batteries set up that far back I flew on the full stabilization mode. A few more on intermediate with segments with stabilization off at altitude.

Also set up your receiver’s rates whether dual or triple rates to keep 100% on the elevator in both or all modes to help hold the tail down on the landing rollout.


Edit, maybe ask on the web to see if someone wants to swap a v1 radial where you can customize the weight filling in the hollow cylinders of the v1 to the degree desired.
Oct 18, 2019, 03:19 PM
ICM
ICM
Registered User
I have a v1 with 1oz of stick-on weights on the foam shelves next to the motor opening with Gens Ace 3s 3300(268g) or 3s 2600(238g 1/2" shorter) as far forward on the tray as they will go. Cg is perfect and flies great off my 1/2 -3/4" grass field. Only nose overs are when I forget and relax the elevator too much on touch down. Considered the V2 dummy engine but given the extra weight and $35 cost, decided to leave well enough alone. Good advice to leave the elevator at 100% on all rates.
Oct 20, 2019, 03:29 PM
Registered User
Dave#13's Avatar

Roll over


Just an update on the roll over problem.
Fixed the broken hinges on the rudder caused by the last big roll over.
Added a carbon rod into the fin.
I removed the dummy engine with it's weights.
Made a replacement "cowl" from the end of a tube of silicon that fits into a "gun" and is used for sealing bath's etc. It's exactly the right diameter to fit over the three lugs that held the dummy motor.
Battery (2900) all the way forward.
I have set elevator to 125% UP and 100% down via the AS3X programmer and my PC.
Also set aileron to 125% both ways as the roll rate is a little less than I would like.

Had 5 flights and 5 good landings with no roll over.
As it is now, it is a little tail heavy, but is still perfectly flyable.
I'm going to make something to hold a weight at the front to correct this - just not sure how at the moment as I would like it right at the front.
Maybe a lead ring around my new cowl!

Got to get brave enough to see if I can open up the dummy motor to remove some weights, as this would be ideal.

Dave.
Oct 21, 2019, 07:44 AM
Registered User
mdmyers's Avatar
Not sure how much your hoping to add but people have replaced the white plastic spacer behind the prop and the prop nut itself with steel parts to add some nose weight and that's as far out as you can get. Access to a lathe makes that easiest but you could also do it with a stack of washers for the spacer and just a solid rod with a drilled and tapped hole in the middle for the prop nut.
Oct 22, 2019, 07:51 AM
Registered User
Trying to decide between this and the Pitts 850mm...

Reason I am leaning towards this: I like the look of the plane more, it's slightly larger, it has seemingly better landing gear for grass landings.

Reasons I am considering the Pitts 850mm: It's a 4s rocket ship. I already have 4s batteries. I love aerobatics (I fly a Timber X right now)

How much get up and go does the PT-17 have? How's it's vertical? Roll rate? I've seen some videos where she looks pretty fast... and does decent vertical, but it's hard to tell in the vids if it's actually veritcal... or just steep climb...

Obviously I am not expecting performance like the Timber X, but would like to be able to do some decent aerobatics... I now the little red pitts is quite capable.

Anyway, your input is appreciated! Thanks!
Oct 22, 2019, 08:16 AM
Registered User
B_Rich's Avatar
Quote:
Originally Posted by Atoms
Trying to decide between this and the Pitts 850mm...

Reason I am leaning towards this: I like the look of the plane more, it's slightly larger, it has seemingly better landing gear for grass landings.

Reasons I am considering the Pitts 850mm: It's a 4s rocket ship. I already have 4s batteries. I love aerobatics (I fly a Timber X right now)

How much get up and go does the PT-17 have? How's it's vertical? Roll rate? I've seen some videos where she looks pretty fast... and does decent vertical, but it's hard to tell in the vids if it's actually veritcal... or just steep climb...

Obviously I am not expecting performance like the Timber X, but would like to be able to do some decent aerobatics... I now the little red pitts is quite capable.

Anyway, your input is appreciated! Thanks!
I just ordered this plane. It uses the same motor and esc as the Pitts 850 so it should fly 4s.
Oct 22, 2019, 08:34 AM
Registered User
Quote:
Originally Posted by B_Rich
I just ordered this plane. It uses the same motor and esc as the Pitts 850 so it should fly 4s.
Well hot damn... Horizon's page says 3s for batteries, but yeah... the ESC and motors on the replace ment parts pages are identical!


THANKS!


So who here flies their stock PT-17 on 4s? How's she fly?


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