Just got my first jet. An A-4F Skyhawk That is done up in a Blue Angles paint sceme. I picked it up at a local swap for a really good price, but I need some help/input to finish getting it ready to fly.
Here is what I know about the airframe+equipment: O.S. .77 Df engine, Century jet retracts, Futaba s3003 servos for flight controls. I'm not sure of the make of the fan unit itself, nor of the airframe. Came setup with 20oz fuel tank+2oz header tank. The fan is in front of the engine.
Now her are the questions.
1. Where can i get a starting probe for this thing? The hex in the nose of the fan unit is 6mm.
2. Can I go with a smaller fuel tank? I typically only fly for 10 minutes or less.
3. Will this run ok on 10% fuel or do I need something "hotter"?
4. Is ther a way to figure the CG for this plane? I don't have the dimensions on it handy.
5. What amount of throw on flight surfaces, % of expo, dual rates, etc.?
I'll try and figure out how to post a picture and the dimensions later so that maybe someone can identify the airframe maker.

I've only had one ducted fan in my life and I sold it after ten flights. I'm sure someone will help you here.

One tip (I use this on all of my jets...) Make sure you have all the elevator you can on a rate switch.

Good Luck!

Raf

Sounds like either a Yellow Aircraft or Jet Hanger Hobbies kit.

The fan is probably either a Turbax II or a Dynamax. If it is a Dynamax then it should take a standard 1/4" hex on the starter probe. The Turbax units usually used a belt or if there was no intake duct the starter was applied directly to the spinner. I don't think they were designed for probe starting. Post a pic and one of us will be able to tell you what you've got.
You can make a starter probe fairly easily with some steel rod, brass tubing, small spinner, silver solder, and the appropriate sized ball hex. Or you can get one from Jet Model Products or BVM.
You'll be lucky if you get 10 minutes from 22oz on a ducted fan, plan on about 8-9 minutes with that setup.
10% fuel is fine, but be sure it has at least 20% oil with at least half being castor.

I'm sure someone else will be able to help with CG and throws once we figure out which kit it is.

Well you guys helped already. went to all the mentioned mfg websites and nosed around. Fan is almost definately a dynamax, but it does have a 6mm hex on the front. Took the same allen wrench as my TT Raptor heli. I'll likely make my own probe after seeing the prices for the not really available units. Do you happen to know of a good source for loose ball end wrenches? can only get sets around here. So far, I am leaning towards yellow aircraft as airframe manufacturer. Foam core wings and fiberglass fuse. I won't go to a smaller tank, but I may try a round instead of square. Fit was very tight, no room for any foam. Also I forgot to mention that the rudder is fixed. is this going to give me a serious problem when trying to land crosswind? Also noticed inflight mixture control while on a couple of the sites. Should I add this?(extra channel is no prob, and should be able to find a spot 4 servo and valve) I will try to figure out how to post pics as soon as i find my darn missing digital camera.

finally got the pictures . Still need a CG location if someone can give me one.

Hard to tell which kit it is from those pics, but just judging by the engine hatch and the exhaust outlet I would venture to guess that it is a Jet Hanger. It could still be an early Yellow AC kit though.
Pull the hatches and get some pics of the ducting.

Re: the fan and starter probe.
6mm is very close to 1/4". If that is indeed a Dynamax fan unit it should be a 1/4" hex. Make sure you use the correct size because they will round out very quickly if you don't. Always use a little lube on the starter probe as well to keep this from happening.

Will post some internal pics tomorrow. As far as the fan, hex is definately 6mm but i don't think the center bolt is original. The hole in the front of the spinner shows evidence of having been enlarged, and the person I got it from said something about having to replace the bolt. Haven't had a chance to make the probe yet but will be sure to use the lube when the time comes.

I only had one ducted fan (BVM F-86) with an inflight fuel mixture. I never used it. But like I posted earlier, I sold it after 10 flights.

A rudder helps alot even in non crosswind conditions, to help line up over the runway. If you have a long clear approach then it is probably a non-issue. I fly in a relatively short field, so my rudder is always paying for itself!

Raf

Here are the rest of the pics. Did everything but pull the fan again. Not too worried about the lack of rudder. May run up the engine this afternoon

Looks like a early Yellow Aircraft A-Fo to me.

You might want to PM Buck (Yeahbaby), he was flying one of those about 6 months ago and probably will be able to help you with CG and throws.

That damage in the spinner could have been caused by a probe slipping. Triple check to see if a 1/4" ball end allen will fit it. It is possible that someone changed it out, but they probably would have had to machine a new fan nut to make it work with a metric bolt. I think it is very unlikely that someone would go to that much trouble.

11 blades,,, about positive its a dynamax, as for the fan pressure I wouldnt reconmend that, i would go with pipe pressure.

Hi,

That's definitely an old Yellow A-4. Kevin is quite correct about the bolt. The 6mm will fit, and even seem snug, but don't spin that unless you're 100% certain the 1/4" one won't fit even better. Otherwise, you'll hog out the bolt with your heli starter (ask me how I know).

As for CG, it's important to know whether you have the scale or sport wing. Can you measure the span?