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Building Tips and technical articles. => 1/2 A building. => Topic started by: Jay on November 25, 2013, 07:40:40 PM
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Anyone have any experience with this engine?
http://brodak.com/engines/engines/brodak-mk-ii-049-engine.html
It looks new and different.
Jay
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Jay, I've witnessed this engine running. I haven't seen it in actual flight. The engine is a very mild run. Engine quality is superior in my opinion. I think it has a lot of hidden power, but that being said it wasn't designed for that and therefore it's design parameters keep it very low rpm's. I for one, am not a fan of standard glow plugs in a 1/2A. This engine would certainly benefit using a Nelson plug/head combo. The crank looks very similar to a Cox Medallion. The fits were tight initially. The engine took a little fiddling to get it running. Once running however, each start progressively got better. I for one hate breaking in engines and this one was testing my patience. Any modern constructed engine today is going to do the same so it's not fair to say the engine is basically a pain in the rear. I also was doing this in the colder temps which as we all know with modern metallurgy the metal can contract. I believe this engine is a AAC constructed engine. Don't hold me to that as this was a year ago. In the scope of how and what the engine was designed for, I liked it. I would certainly like to see say a crankshaft available that is higher timed like the Cox TD which would wake the engine up for my style of flying. Ken
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Hi Jay,
I have bought two over a year ago for the baby flite streak and lightning streak.
As Ken said, it took a little bit of fiddling to break it in. I find it very sensitive on the needle.
I tried 10% and 25% nitro on mine and it definately needles better with 25% amount of nitro. Not perfect, but better.
I'm not an expert with 1/2a engines. Maybe this is a trait with all 1/2a engines in general.
Maybe Ken can confirm this. Ken knows his 1/2a stuff.
Now that it is broken in I need to build the planes for the engine.
-Dan H^^
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I've had one like it on a test stand in the shop since July, but haven't gotten around to flying it yet. It's destined for a Brodak P-51 Mustang. It is an AAC, so needs no special treatment to break-in, just a few runs alternating between lean and off-peak. Then bolt it on and let it finish breaking-in in the air.
The first start was difficult as I didn't realize at the time that it's very easy to flood this engine. And I also found the head bolts, straight out of the box, were not fully tightened. I finally got tired of flipping and zip tied a Norvel starter spring to it and it lit right up, easy as pie. Ever since then each run has been better. I've only used Sig 25 in it, and now after a few runs it needles reliably. Be careful priming it, it doesn't like to be very wet to crank.
Rusty
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Hi Jay,
I have bought two over a year ago for the baby flite streak and lightning streak.
As Ken said, it took a little bit of fiddling to break it in. I find it very sensitive on the needle.
I tried 10% and 25% nitro on mine and it definately needles better with 25% amount of nitro. Not perfect, but better.
I'm not an expert with 1/2a engines. Maybe this is a trait with all 1/2a engines in general.
Maybe Ken can confirm this. Ken knows his 1/2a stuff.
Now that it is broken in I need to build the planes for the engine.
-Dan H^^
What RPM/Prop are you getting?
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Herman, I've seen some real rpm differences with this engine. While our initial test yielded around 17k on a Cox black 5x3, the engine really came alive using a APC 5x3. We had put some nitro to ours and we saw a high 21k almost 22. We didn't try flying using this engine. I can't say if the added rpm's are a advantage or were just beating air. I did post a picture of the engine running on here some time ago. Some may feel this is close to Black Widow power, but I've never had a Black Widow run to the consistency of this engine. Ken