Tuesday, April 8, 2014

Wayne's Yak re-build.


10 years from now we will probably have a fuel meter on our transmitters but for now we just need to remember to fuel up by relying on our distracted brains. Poor Wayne was ever so excited to get in his first flight on our second day at a giant scale fly in. He put plenty of smoke oil in but whoops that’s all folks. Of course you only run out of fuel when you are in a hover 3 feet off the ground.

As I stood next to Wayne watching him fly as his spotter the last words I heard him say were “Oh Sh%t” and then thud. It just sat there so peacefully waiting for us to gently roll it over and shed a tear as we carried the many large and small pieces back to the pits.

Sooooo we re-build………..

The plane fell over on its back and landed upside down motor first so the engine box snapped in half as well as the rudder. The wings got a couple surface cracks on the tips.

Rule #1 save all the parts to examine later, thankfully we did. When I was not so excited and distracted I was able to focus while it was spread out over the bench and I could make a plane. I would piece together the engine box and trace for new parts.

I ran a re-enforcement 1/8” ply down the inside of the fuse to help sandwich and secure the new box. Since I was able to trace the old parts, lining up the new firewall was easier to get the right angle and down thrust. For the firewall I laminated two 3/16” ply together for extra strength. The firewall is glued in with 30 minute epoxy and clamped for 24 hours to dry.

The only new parts needed other than wood is a cowl and the spinner. The engine will be shipped off to DA to be inspect and repaired as necessary. Oh and a prop.

Tomorrow I install the re-enforcements and start on the bottom of the fuse where a couple stringer snapped.

Broken bottom stringers.


The parts:(

Just not enough!
These tanks are made for 3D flying. The clunk may seem short but for 3D its not. The clunk needs to be able to move all the way around and back quickly.

Laminating the firewall.


Glued with CA to trace the sides.

Firewall glued and clamped in place for 24 hours.
 

Tuesday, December 31, 2013

SBACH - Pilot RC 35%

 
Build/Review SBACH – by Pilot RC
After building the last two airplanes and selling them I decided to do one for myself and dust of this Sbach I had custom covered from Tony at Pilot. It’s been sitting in the corner of the shop for a few months.  I have a brand new DA 120 for it and will be using BLS157HV’s all the way around.  The design of the wings on the Sbach are similar to the Edge and lend itself to stability in a harrier. The straight leading edge and light tapper on the trailing edge help lock in the plane and deter wing rock.
I hope to make this build as entertaining as possible with some cool custom covering work on the internal parts of the plane. 
Unboxing
I have built planes from most the entire top brand manufactures except one 3D Hobby.  They all have learned through trial and error how to best ship I think but I am always happy with Pilot’s solid packaging.  It’s no secret that I am partial to Pilot and friends with Tony the owner but no one company is perfect and I always like to give honest objective opinions and I have a few on this build.
I have built most all the Pilot planes and I have learned that buying direct from Pilot has some major advantages although you will pay a little more for shipping.  When shipped from Pilot direct the boxes have minimal handling.  They don’t get crammed into a container and sit waiting to be loaded on a ship and then unloaded, trucked and unpacked again only to be moved over and over again as sales staff search for planes to be shipped from a us warehouse.  From Pilot direct DHL picks it up and ships it direct to me in three days so the only hands on after leaving Pilot is DHL. Makes it hard for DHL to deny anything.  The best part is the custom schemes.
Spats First
I always install my trademark Spats first on my planes so it has something to sit on.  I painted the Spats to match the scheme.  I will be installing smoke so I am going to seal and fuel proof as much as possible while keeping the weight to a minimum. I sealed all the wood under the gear and in the exhaust tunnel.  The covering job was excellent so little iron and heat gun work was necessary before sealing the important seams.  I filled the Spats with Whiterose wheels and titanium axels. They not only look cool they are very durable and I have never had the rubber roll off the rim.  I also used a Whiterose tail wheel with a straight wire tiller arm to relieve the rudder servo of stress and use less battery to work the rudder servo.  Spring tensioners tend to make the servo work harder.  The factory tail wheel from Pilot is actually one of the better ones I’ve seen come with a kit and I have used them in the past.  
Control Horn Details
I always like a finished look so I paint all my control horns to match the planes scheme.  Sometimes I even use colored ball joints to match but on this plane I use black all the way around which brings me to one of the honest reviews I need to make.  I have noticed more often on the last few planes from Pilot the hardware has been lacking in quality.  In fact some of the nuts included had absolutely no threads on them.  My confidence is bruised in the hardware so I replaced most all of it on this plane with RTL hardware.
Rudder Servo In The Tail
The Sbach is one of the few Pilot planes that have a pre designed spot for the servo in the tail, most other planes need to be custom designed and installed.  I have seen several where people get the geometry wrong and proper smooth operating is not executed effectively.  I made the same pushrod I always do with a carbon fiber rod set up. This has no flex in it and gives the rudder such a great feel. No slop or delay causing over correcting.  I use one servo on the 100cc rudders as long as it’s powerful enough.  I also re-enforced all the glue joints around the tail where the servo mounts.
Switches and Fuel Dot
A while back I put the Fromeco switches to test. While getting a little loose, careless and to low with my Decathlon I put the spinner in the tail.  I bravely used the Fromeco switch again in another plane and on the third flight it failed but failed ON as it’s supposed to operate. The Fromeco switches can be a little challenging to install but the durability is worth it IMO.
I like Mcfueler fuel dot’s, they are solid and easy to use and do not twist the fuel tubing. I installed one for the fuel and one for the smoke oil with nice big labels so as to not make the ultimate mistake and smoke the fuel if you know what I mean.
Engine
I am using a DA 120 with Pro Flow cans. Had I not finished so much of the radio and fuel tank installation I would not be so upset at this point.  I never would have expected to find what I did with this plane. I have built all the other Pilot RC planes and expected the can tunnel to be of normal size to fit normal cans. Well to my surprise it’s made several inches short. Your choice is to cut the back out of the tunnel for the cans to extend back further which I would do next time or cut the headers short. I cut the headers which means the engine may have a slower response on the low end and most of the power band on the top end.
I can’t imagine what Tony was thinking, this may be the biggest design flaw on a Pilot plane I have ever seen. Had I known about it from the beginning I would have made adjustments. It would be nice to get a disclaimer in the plane stating the tunnel was designed for a cox .049 engines exhausts!  Next time I talk to Tony I will be voicing my cheap opinion. 
Have you ever wondered why two identical planes can fly so different?  I never just mount the engine to line up with the cowl. I block the plane level and check the incidence on the tail and wing to match the engine with the correct down thrust and side thrust. Rarely will it line up perfectly with the cowl.  Twice I have removed the cowl ring on planes and re-glued them. I know this works because the last three planes I built needed no trimming except for one click up elevator.  They fly true straight in any angle.  This plane was no exception and I had to correct the cowl just slightly.
Radio Install
I did a custom install similar to this on another plane recently and couldn’t wait to do it again on a plane for myself.  It adds several hours to the build but the result is what you see, just awesome looking!  I balance my planes before I even start the build. After placing certain parts where they must go i.e. engine, cans, servos, tank etc. I then place the batteries and any other parts on the CG point and start moving them out to the closest mounting point so as to keep the weight as close to the center of gravity while keeping it balanced.  This way I am not moving weight around to make up for weight somewhere else.  By keeping as much weight to the center of the plane at the CG point makes for a good responsive, clean flying plane.
Final thoughts
This plane has a great flying reputation and is considered to be one of the most stable 3D planes available.  The plane is built as usual from Pilot RC, very good.  The wood is quality and appears to have no weak defects and the covering was applied well and tight, it needed very little re-heating.  Some of the hardware was not up to the quality I was expecting from Pilot. The can tunnel needs to be redesigned.  One of the best features of Pilot RC planes is the ability to order custom build options and color schemes. Pilot RC did a great job with all the custom features and covering I asked for. 
Thanks for reading, 
Spats