A return to model building and flying. Part 46

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December 2007

Computers,  *!!&%!*x*!...!

Not all that much going on this month. With Christmas arriving and making time for my other hobby of messing about with computers, which in this case involved building another computer form old and new parts; doing all this was long overdue and I have been putting it off for some time. Then completely reconfiguring my small network, followed by bludgeoning the whole thing into life. This has taken nearly two weeks; probably three solid days at one point. My Internet service provider messing about with their own network at the same time, and my web host resetting all the passwords didn't help either. 

With all the data I have to store and work with these days, it's not just a case of switching off one PC then switching on another any more. I think it's called data integrity and security in the trade. 

I also always have a second PC networked to  run Microsoft Windows (whatever?) for testing purposes, or running the odd application that Microsoft has spit it's dummy out of the pram about and not let Linux developers have a fair crack of the whip at, or any one else for that matter; as well as testing different distributions of Linux. Also at a pinch it acts as a backup if something goes wrong with my main Linux box. So not so simple any more. And you thought aeromodelling could be involved and frustrating?


Not much, due to the weather and what has been mentioned above; but a lot of modifcations.

The first under the knife was my open class club racer, with a heavily chopped down wingspan and removing all the tip weight to try and reduce some of the line tension. it's not flying fast in racing terms, but the pull is enough to make holding the handle with both hands a necessity, as I can start to get cramps in my right arm near the 50 lap mark.

The Brodak Buster continues to give me problems, which is annoying as I have just about sorted the model out, but every time I change the tank to get more or less flight time, I get a whole new set of problems. I should really just give in and make all my own tanks; time consuming, but they at least work properly.

The Hellcat has had yet another engine graft in the form of an MDS 48 (that makes every size of engine beween .32 and .48 in this model so far), to see if I can get a hike in performance and still retain some reliability. It's a hell of lump of metal, but strangely is the same physical  size as the SC.40's I have used, but weighing almost the same, so it must be an optical illusion.

Somehow I ended up with two of these engines an new one, Ripmax are off loading their old stock, so there are a lot out there at low prices; no backup, but who cares; and another one that was given to me by Bob S. Cheers Bob. I also now have an MDS.58 which is an even bigger brute, and is, definitely, bigger and heavier, so that one will have to wait for an appropriate time or model.

The one I used was Bob's. It has compression that would not disgrace a diesel. which means being a bit careful when starting. It responds well to back flicking, so it's not really an issue. It is, like most MDS engines, on the heavy side. Again, not too much of a problem as a forward CG on a carrier model is not necessarily a disadvantage.

 Like all the MDS engines I have owned, this one starts easily and throttles very well. Tracking down the older type MDS carb's is not so easy, but I finally managed to find one on eBay. If you don't know what I am on about, read my previous ramblings on the subject.

The supplied MDS  'Super Quiet Silencer' is exactly what it says on the box, and is also reducing the power quite a lot; but as it has a quiet sophisticated twin baffle system, I removed the rear baffle to compare the difference. This produced a noticeable increase in speed without too much of an increase in noise. This is very useful to know, because it cured another unwanted feature.

When trying to set the main carb needle with the fully baffled silencer, I noticed it was very difficult to set up for full speed, being very easy to set the engine too lean without the engine showing any signs of distress. This would resulted in a couple of laps and an engine cut out. Trying to set it richer was just as difficult, usually ending up with the model loafing about trailing a plume of smoke. Removing the rear baffle has improved this behaviour, making the needle setting much less insensitive.

The original MDS SQ silencer would be fine in an RC model with a large prop, the exhaust note would be reduced to a whisper. However I am looking for a bit more brute force and ignorance (as the saying goes).

The only problem now is, getting the engine to throttle slow enough. This engine has so much torque that it will climb on a mere whiff of throttle. A finer pitch prop may help this, but the top end will suffer. Now I have most of the big problems sorted, it may be just down to setting the carb up properly.

Getting to this point, I was enjoying flying the the model flat out and low when I was momentarily blinded by the low setting winter sun. The result was an  abrupt stop! aaaaannnd I was presented with the view of my model looking as if it had speared the ground, engulfed in a plume of rising steam. I thought that the the end of the Hellcat was nigh. But, upon digging the nose out of the ground from the end of a deep trough cut in the turf, the only damage was a broken prop. I thought maybe this is a good time to call it a day. Signs and portents, and all that.

SIG Manufacturing

Further to my mentioning last month that I had ordered some three blade props from SIG in the USA, I was beginning to get  a little concerned when the postman left a note saying I had missed a parcel delivery. The next day the one I was expecting arrived, so I guessed that this was the missing parcel. If it had been the props from SIG they must have come over by military supersonic jet.

As time when on, I began to wonder what the missing parcel was, and indeed if it was the props after all.  Of course by this time I had thrown the note away, and even finding the telephone number of the returned mail department was not easy, I could not find it listed anywhere. When I eventually got through no one could find anything, so I went back into standby mode. But still had this nagging doubt in the back of my mind.

The SIG site was by this time showing DISPATCHED against the order number, but if it was It would have been here by now, and there was no money deducted from my account? Being even more puzzled I resorting to plan B, I emailed SIG; to their credit I had a reply the next day, apparently waiting delivery of Master 8x6 x3 props. Not to their credit, signing off on an order when it patently wasn't complete, and not informing me of the delay.

This has been an experiment to see how easy it is to deal with other businesses in the USA. so far Brodak has a thumbs up. The jury is still out on SIG.

F8F Bearcat 

No Progress on the Bearcat this month.


The other thing I am experimenting with, is converting an ARTF RC electric park flier to CL, just to see if it can be done.


The model in question is an 'Ultimate-ep' biplane. I had been impressed with this model ever since I saw one in the local model shop. It features a properly built up structure, it's not a foamy, and I have no problem saying that it is beautifully designed and constructed. 


I guessed it would take a minimum amount of work to convert to a flapped stunter, and I have always wanted a biplane stunter. It is already looking like I may be wrong in that assumption. The first big problem has been the engine cowl. After initially fitting a radially mounted Irvine .20 and cutting away the cowl to fit, there is so little left, that It may be easier to just make a new cowl around the Irvine engine.


remove elec mount

The first job was to cut off the electric mounting, then reinforce the bulk head with another 3mm ply doubler epoxied inside. This allows a standard  radial mount to be bolted onto the front. 


radial mount

To utilise the existing cowl the same thrust line has to be use which meant the engine ended up being a little high. The result of this was the silencer fouling the fuselage. Luckily A dustbin silencer just fits, but now there is so much clutter, the cowl is rendered almost unusable.

The cowl has been so cut about now, that making a completely new one tailor made for this setup, is stacking up to be better option.

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