Jamara Pitts S2B
- final stages of the build
This page concludes the build of my Pitts S2B and follows on from the wing build page.
As is often the case with a build, the last 'fiddly bits' seemed to take as long to get up together as the rest of the plane! The undercarriage assembly included wheel spats which had to be made up from several laser cut pieces and then sanded to shape, but didn't include the fairings. I thought that the Pitts wouldn't look right with only aluminium on show so I crafted some fairings from balsa.
The control horns supplied by Jamara are 1/16" ply horns with just a single hole for the linkage. I didn't particularly like the look of them so ordered some standard white plastic horns from SLEC, although I did use the ply horns on the lower/upper aileron linkage.
My choice of servo was the Etronix 9g micro servo; I've used these in a glider and they are excellent value units at around a fiver a piece! They are fast and deliver 1.6kg/cm of torque and no modifications to the 4 servo locations were needed as they were the recommended size.
For the powertrain components I'd decided not to go with the recommended Jamara motor but instead opted for a Scorpion system. After deciding on a S-2215 I found out that there were stock issues, so Andy at Micron Radio Control suggested a Tower Pro 2409-12 as a suitable substitute, with a 30A ESC. My pack of choice was a 11.1v 2200mAh Zippy Flightmax pack from Hobbyking.
Sourcing a suitable pilot proved to be another problem so out came the balsa block! It's been a few years since I've had to carve a pilot and it showed, my guy bore a striking resemblance to a caveman when he was done. Still, he sort of looks in control....
Covering the Jamara Pitts S2B was eventually done with a mix of metallic red Solarfilm, metallic blue Oracover (Profilm) and white Solartrim with blue pinstripe (Trimline). Now I had never used Oracover before but I wanted to give it a go - having tried it I think Solarfilm still stays my preferred choice! I had big problems when it came to shrinking the Oracover and I think that the relatively weaker (relative to bigger models) structure of the Pitts was a contributing factor; as the film pulled tight it distorted the framework and as a result just wouldn't achieve its complete tightness, or that's what seemed to be happening in places.
After two attempts (I hate undoing anything that I've just done, grrr!) I decided to go with Solarfilm and changed the colour scheme in the process. The only Oracover I ended up using was the blue on the bottom half of the fuselage.
After covering, the balsa inside the cockpit was painted matt black and my caveman sat in place before the clear plastic canopy was fixed in place with canopy glue.
Fitting the motor proved to be somewhat troublesome, not helped by the fact that two of the mounting holes had been machined incorrectly and so I had to redrill and rethread them with an M3 tap. Actually getting the motor in place was tricky to say the least, and I had to make up a small ply plate to give the recommended down thrust.
So here are a few miscellaneous photos of my Jamara Pitts S2B in its final stages of the build, click to view larger:
Above left: ailerons & undercarriage parts. Right: my caveman pilot!
Above left: the reinforced undercarriage plate. Right: rear wing fixings.
Above left: lightweight filler was used where needed. Right: The sanded cowling.
Above left: the bare airframe, minus control surfaces. Right: job done!
Jamara Pitts S2B flight report
As yet (Jan'11) unmaidened due to weather and time constraints. It could happen anytime, so watch this space! The closest it's come yet is a ride in the plane balancer to get the Centre of Gravity right. Fortunately no extra ballast was needed but of course this could change after flight tests...
Final report
The very first time I saw the Jamara Pitts S2B advertised I wanted one. My expectations of the kit were based on the glossy photo of the exquisitely finished plane, and these expectations turned out to be over-inflated. I have no problem with admitting that I was disappointed and sometimes extremely frustrated with the quality of this kit; too much vital information was left out and the wood selection and laser cutting could definitely have been better.
Without prior building experience this kit would have been an absolute nightmare and I dare say would never have got finished! Would I recommend it? The jury is still out on that one... I absolutely wouldn't recommend it to a beginner just entering the building side of the hobby, there are much friendlier kits out there. As for recommending it as a nice plane to have and fly, I need to get the thing maidened before I can answer that!
Incidentally, since the build a member in my forum enlightened me to the fact that the Pitts kit is manufactured by German firm Balsaworx, so it's unfair for me to blame Jamara for all the issues I had with the kit!
If you've got or are building the Jamara Pitts S2B, share the experience in the forum.
