Sig Rascal 110 ARF Build

Joker 53150

Mmmmmmm, balsa.
Mentor
I'm self-quarantining the heck out of myself in the shop over the weekend. Luckily I can work from home the next few weeks until everything calms down. Now that I know the Rascal flies I figured it was time to tackle a job I really hate - carving holes in the cowl to fit around the carb, muffler, spark plug boot, etc. As you can see I made a few "extra" screw holes during the process. :oops: A little final trimming followed by more primer is needed for the gas line and to allow for more airflow into the cowl for cooling. While I'm not a big fan of a fully exposed carb, I do have easy access to the high & low jets and choke. A 3" spinner was ordered to help finish off the nose (the little spinner is just there to let me use an electric starter in the meantime).

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clolsonus

Well-known member
Just my random opinion, but I think the Rascal is one of the masterpieces of RC model airplane design. It has all the looks, all the performance, and all the nice flying qualities, all at the same time. I count myself fortunate to have met Scott Christiansen (the designer) in person before he passed away.
 

Joker 53150

Mmmmmmm, balsa.
Mentor
Just my random opinion, but I think the Rascal is one of the masterpieces of RC model airplane design. It has all the looks, all the performance, and all the nice flying qualities, all at the same time. I count myself fortunate to have met Scott Christiansen (the designer) in person before he passed away.

I agree, it’s a beautiful design. There is a knock off of it that looks good, but is missing about 25% of the character the original has.
 

Joker 53150

Mmmmmmm, balsa.
Mentor
Three more flights on the Rascal today, and I also found out the max flight time is around 15 minutes before fuel runs out! :eek: The first two flights were uneventful and 5-10 minutes each. The third flight I was waiting for my buddy to land, figuring I had plenty of gas left. I made my first approach and the engine wouldn't idle down enough for landing like it had the previous flights. It didn't concern me too much until I applied power to go-around for a second approach and the engine was hesitating a bit. After a few seconds it was running well and I did a lap and lined up for my second attempt. Same issue, it wasn't dropping RPMs like it should so it was still a few feet off the turf and well past me when the engine quit. Thankfully, this is a sod farm and the treeline was still about 1/2 mile away! :) With the engine dead it finally came down for a perfect dead-stick landing. When I returned from my long journey to get the plane I checked the tank and it was empty. Well, that'll teach me to set a timer on my transmitter. :oops: The RPMs wouldn't drop as the engine was running lean. I'll say it again, this plane is a joy to fly, possibly my favorite right now.
 

TooJung2Die

Master member
Three more flights on the Rascal today, I'll say it again, this plane is a joy to fly, possibly my favorite right now.
It's a beautiful airplane with classic lines and great presence in the air. Can you post a photo of the whole airplane with the painted cowl?
 

Joker 53150

Mmmmmmm, balsa.
Mentor
A couple more flights on the big Rascal and a small problem popped up. I noticed the engine wasn't running as smooth or consistent as it should, so I landed and started inspecting. I think the problem is fairly small - bubbles in the gas line. This could have been from the gas tank vibrating and the clunk picking up some air, or one of the fittings isn't tight and is letting in a little air.

To test the tank I filled it completely and watched the gas line and tank as we ran it up on the ground. The fuel in the tank was vibrating, but not enough to be the issue - and air bubbles were abundant in the line. So my issue is somewhere between the gas tank cap and the carb... Yay...

I figured the best option was to pull the tank and inspect each connection. Pulling the tank is a pain in the butt, as I have to pull the carb, muffler, prop, cowl, windshield, and dashboard. Once this was done and I had easy access to the full fuel system I found the cap on the Fiji bottle could be tightened a very small amount (probably not enough to have been my leak), and the fuel filter also had a little play in it. The filter is the more likely source of the bubbles as the O-ring was slightly bulging in one spot. The filter was replaced, the tank re-installed, and I put additional foam padding around the tank to hopefully keep the fuel a bit more isolated from vibration.

Another issue is shown in the pic below - a crack in the carb isolator. I knew the crack was there when I helicoiled the hole a while back. It's on the outside of the isolator and doesn't create an air leak into the air/fuel mixture, but it's something I need to watch. So far I haven't been able to find a replacement piece as this version of the XYZ (Turnigy?) engine is discontinued and the new version uses a rear-mounted carb. With the plug, carb, and muffler removed I was also able to inspect the piston, cylinder, and spark plug. I've run the engine a little over an hour since starting this project and the cylinder and piston (at least what's visible) appear to be in great condition. The plug is telling me it's running a little lean, so that'll be the first thing to check when the air bubble problem is solved.

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Joker 53150

Mmmmmmm, balsa.
Mentor
Let's just say mistakes were made... :cry:

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I was doing some asphalt repair and put a wheelbarrow holding a big bag of asphalt patching mix in my garage. The next morning I went to move it and accidentally tipped it over. On the way to the ground it hit the horizontal stab of the Rascal which was sitting on my plane rack. Luckily the only damage was this entire assembly broke loose from the fuselage, which will be an easy fix.

While the tail is being worked on I pulled the cowl to give it another coat of white paint and to try and find the source of a small air leak which is keeping the engine from running correctly. The last time I flew the plane I noticed bubbles in the fuel line. I think it was coming from the fuel filter area and not the fuel tank, as the tank is a pain to remove. Good times...