Sport PAU 27% Pitts Challenger Build/Review
- Thread starter Bartman
- Start date
combat chicken
100cc
From one Bart to another Bart, great looking bird. I have a GP Ultimate 1.60 that is in the box that will be emerging to see the light in the next few weeks so your suggestions/ideas on the pitts build will come in handy. Thanks for doing this! 
Bartman
Defender of the Noob!
OK, so the airplane is done and we had a chance to get it out and fly it yesterday. I was going to try to do a wrap up video of the build before posting the flight results but with the kids home and an epic honey-do list waiting for me at every turn, it'll have to wait.
Here's the flight report;
But first a big thanks to GiantScaleNews.com member Earle Andrews (aka @Pistolera ) for volunteering to do the first flight!
The airplane has a bone stock slightly used DA-50 that I picked up in the classifieds......it ran perfect and pulled the PAU Pitts around with authority using a Revolution 22x10 prop. The next round of flights will use the prop recommended by DA, a 22x8 for lower top speeds and to put the engine in a better RPM range for the flying I'll be doing.
The airplane balanced right at the spot recommended in the instructions yet it appeared to be very tail heavy in the air. To be fair, in my haste to get it assembled I attached one I-strut incorrectly so the balance issues may have been caused by the wings being free to flex slightly on one side. I'm going to replace the pitts style muffler with a different and much heavier pitts style muffler to see if that improves the balance condition.
Aside from the balance problem, the plane tracked through the sky beautifully and was way more responsive on low rates than we expected which means the high rates are going to be very very responsive.
The balance issue was enough to keep us from doing more than two short flights so there will be more to report as we go and I definitely want to do a quick Pro's and Con's summary for anyone planning to purchase a PAU 27% Pitts Challenger. The issues I had in the build were minor and I think the end result is a great looking airplane that does well on stock 50cc power and which fits easily in a standard sized hatchback. The plain red scheme lends itself to just about anything you can dream up so drag out all of your Ultracote/Monokote scraps and make it your own!
All in all, I'm very happy and can't wait to fly it again. I did the second flight myself but after we saw the balance issues (and what might have been a thrust line issue) I handed over the transmitter to Earle and let him do the second landing. We'll adjust the balance, make sure the wings are attached correctly and fly it some more with a report to follow. Thanks for reading! Viva la GiantScaleNews.com!
Here's the flight report;
But first a big thanks to GiantScaleNews.com member Earle Andrews (aka @Pistolera ) for volunteering to do the first flight!
The airplane has a bone stock slightly used DA-50 that I picked up in the classifieds......it ran perfect and pulled the PAU Pitts around with authority using a Revolution 22x10 prop. The next round of flights will use the prop recommended by DA, a 22x8 for lower top speeds and to put the engine in a better RPM range for the flying I'll be doing.
The airplane balanced right at the spot recommended in the instructions yet it appeared to be very tail heavy in the air. To be fair, in my haste to get it assembled I attached one I-strut incorrectly so the balance issues may have been caused by the wings being free to flex slightly on one side. I'm going to replace the pitts style muffler with a different and much heavier pitts style muffler to see if that improves the balance condition.
Aside from the balance problem, the plane tracked through the sky beautifully and was way more responsive on low rates than we expected which means the high rates are going to be very very responsive.
The balance issue was enough to keep us from doing more than two short flights so there will be more to report as we go and I definitely want to do a quick Pro's and Con's summary for anyone planning to purchase a PAU 27% Pitts Challenger. The issues I had in the build were minor and I think the end result is a great looking airplane that does well on stock 50cc power and which fits easily in a standard sized hatchback. The plain red scheme lends itself to just about anything you can dream up so drag out all of your Ultracote/Monokote scraps and make it your own!
All in all, I'm very happy and can't wait to fly it again. I did the second flight myself but after we saw the balance issues (and what might have been a thrust line issue) I handed over the transmitter to Earle and let him do the second landing. We'll adjust the balance, make sure the wings are attached correctly and fly it some more with a report to follow. Thanks for reading! Viva la GiantScaleNews.com!
Last edited:
Bartman
Defender of the Noob!
And thanks again to Nick at Nachos Cheese Graphics for jazzing up the Pitts with his GSN designs
@I Love Nachos
@I Love Nachos
Pistolera
HEY!..GET OUTTA MY TREE!
Bart forgot to mention....THERE WAS BLOOD!!!!!!! 
Seriously, it is a VERY nimble plane and even with low rates the first snap I did was a 1 1/2.....just blurry fast snap rolls. Ailerons were touchy even on low rates, so more expo needed and/or a little less throw. Pitch was also touchy, but with the aft CG that should improve a lot. Even though the static CG was right where the manual calls for, when the sticks were released on an inverted 45 it nosed up the vertical very quickly, although the down elev trim for level flight exaggerated this.
As Bart said, we only flew it 2 flights, so couldn't really do much fine tuning of anything until he gets some nose weight (muffler) up front. Then re-trim and start over. It was fun to fly and looks great! Approaches slow down nicely like any biplane (lots of drag) and it almost lands itself.
It was really great to finally meet Bart and get to know the other "half" of GSN
. As Cap't Jack would say...."Arrr" 
Seriously, it is a VERY nimble plane and even with low rates the first snap I did was a 1 1/2.....just blurry fast snap rolls. Ailerons were touchy even on low rates, so more expo needed and/or a little less throw. Pitch was also touchy, but with the aft CG that should improve a lot. Even though the static CG was right where the manual calls for, when the sticks were released on an inverted 45 it nosed up the vertical very quickly, although the down elev trim for level flight exaggerated this.
As Bart said, we only flew it 2 flights, so couldn't really do much fine tuning of anything until he gets some nose weight (muffler) up front. Then re-trim and start over. It was fun to fly and looks great! Approaches slow down nicely like any biplane (lots of drag) and it almost lands itself.
It was really great to finally meet Bart and get to know the other "half" of GSN
. As Cap't Jack would say...."Arrr" 
Jetpainter
640cc Uber Pimp
Nice guys!
rcbobp
70cc twin V2
I have the PAU Bulldog, so my notes will be of some help. First, even if you have it balanced at the correct CG point, the plane has a shorter fuse than other bipes. That makes it more sensitive on the elevator. You can adjust the travel and be fine.
My big problem was the tendency to tip over especially on grass runways. I moved the landing gear forward about an inch and a half. Made all the difference.
Enjoy the plane. It can be a handful at first, but with time you will tame it!
My big problem was the tendency to tip over especially on grass runways. I moved the landing gear forward about an inch and a half. Made all the difference.
Enjoy the plane. It can be a handful at first, but with time you will tame it!
thepamster
70cc twin V2
I was wondering what happened with this project. Congrats on the maiden and thanks for sharing this with us.