Here is a list of all the postings Martin McIntosh has made in our forums. Click on a thread name to jump to the thread.
|Thread: Precedent Stampe 1/4 Scale|
Just got the 180 in mine as a replacement for the 155 which is now in my new Spit. Not too bad a job after sawing off the front part of the engine bulkhead so that it could be replaced with a wider piece; even the cowl fits without the baffles fouling. Will try to strip the bubbled paint from the u/c fairings and generally tidy it up whilst it is disassembled.
Don`t understand what you mean Steve. Can you perhaps post a pic of the part? Do you mean where the opposing wires meet, if so, I did not bother on mine.
|Thread: The Ohmen|
As you can see from my pics I covered the fus. with metallic and painted the cowl over tissue and dope, by far the easiest way to do it. By the way, that looks like a very neat job.
Edited By Martin McIntosh on 22/07/2019 17:20:35
On this one I have used super light wheels which are unlikely to alter the cg measurably.
It is now definitely not the thrust line. The wing incidence should be as per plan. As I said, the laser is not that precise, indeed a click or two on the elevator trim could alter this reading considerably but it is a good guide.
Currently trying to modify a split mount to get the 155 in. Not easy.
|Thread: Moon landing|
I have sat back and had a good laugh at you all once again. You are easily stirred up arn`t you. Keeps the forum alive. Must think of a new subject for next time that things get a bit quiet!
Thanks to all for the informative replies though.
G.S., thanks for calling me a troll. I am only reporting what I saw when it supposedly happened.
That video looked quite good, maybe too good compared with the earlier transmissions. I was referring to the Apollo 11 lift off, not the later ones.
It only goes to confirm my suspicions that this lot was fabricated because they often forgot to put in the 2.5 sec delay between instruction/response/confirmation, especially towards the end when they were actually talking over each other.
I accept that many thousands of people were involved but it would only have taken a handful, suitably paid a few $m each to keep quiet and dupe them, as well as the rest of the world.
Kennedy said that it would happen before the end of the decade. The Yanks would have looked very foolish if they did not come up with something by then.
More brickbats expected!
Measuring with a straight edge rather than the laser, the incidence is most likely accurate to the plan. I cannot really see me having been that far out here.
As I said Jon, unlike some others I am in no great rush for one but just please let me know when it is available. It is only for my old Spit. when I swap the motor to the Stampe.
|Thread: Moon landing|
Some of you will no doubt remember that I put a thread on here a while ago regarding a theory that this was all done in Hollywood. Many hundreds of generally nasty replies from people calling me a lunatic etc.
I have watched most of the recent stuff on TV and was slowly coming round to believing that it actually happened until I saw one of the `take offs` again. A few sparks, no dust, no flame from the rocket and the camera tilted up with the craft, and please don`t tell me again that it was controlled from the Earth. Why did it stop when it did and not follow the craft up further?
Also, on the `landings`, we can hear every word said by the crew with a rocket motor inches below them.
NASA have recently admitted that a Mars mission would not be possible until they found a way to get through Earth`s radiation belt without frying the crew.
I rest my case.
The only plugs I use are Enya 3, OS 8 and OSF. Always best to buy these on ebay on a card of ten or so which works out at about £2.50 each. Genuine ones too.
As I see it, anyone buying a large quantity of every component in an engine must be hoping to assemble and sell them on. Tell them to `go away` Jon. We need the spares out here.
And by the way, I am now in the market for another 180 when you have one available, no rush.
Whilst using the laser meter today I noticed that the elevator had developed a lot of play. On investigation I found that the servo arm was not seated properly and was a bit loose. Changed it and problem solved. This, however, would not cause the trouble I am having. (I think!).
Checked them both with a Great Planes laser meter, not entirely accurate but a good enough guide.
Wing incidence. Old, 1.8 deg., new, 2.6. Error may be due to friction in the laser bearings.
Down thrust, (difficult to measure because of the weight of the meter), old, 1.5 to 2.0, new, 1.5. All readings w.r.t. the tail.
So no real difference anywhere here. Must be down to the cg.
Now attempting to do the motor swap. I can fit the 155 in the Spit by using a tapped alloy plate behind the mount but the Stampe will be rather more difficult.
Incidence cannot be far off because at cruising speed it is OK ( compromise between high and low speed regarding elevator trim, if that makes sense). I have a laser incidence meter so shall try this on both of them next. The maiden generally required no trim changes at cruising speed.
Nosing over on landing, bar the u/c position, is caused by the use of flaps which tip up the T.E. of the wing just when you do not want it. Trouble is if they are retracted too soon then the model will fall out of the sky.
I use lots of expo and have set the throws and everything else as per my original so this is not a problem. The only thing that I have noticed here is that the roll rate on this one is faster with the same set up but this is almost certainly due to the lighter wing.
It is indeed the TN 72" one. I now think that moving the cg back a bit would help. I may have the extended u/c a tad further forward on the new one because it does not tend to nose over on take off/landing, surprising since the cg is now so far forward of the old one which switchbacks on take off and difficult to control, but is otherwise impeccable.
|Thread: Pushrod Transfer Links|
Trouble is that every link can introduce slop or even worse friction, especially if they are quicklinks. I have not used one of these for years now and only fit friction free ball links to each end.
Good God, what is that thing? Never seen one before. What is wrong with putting the servo on the opposite side of the model to the push rod exit, thus enabling a perfectly straight rod to be used? I cringe when I see doglegs of any sort on these. All of my current elevator rods are now hard balsa/hardwood/carbon depending on the model. Wood is the easiest since it is simple to bind a threaded rod to each end. You may require a slight bend in order to align with the horn.
Having now repaired a broken u/c caused by trying to land 3ft above the runway, I have now turned my attention to the t/l. Checked against the old one w.r.t. the wing c/l and discovered that it is actually about 1/3rd further down already, (basically it be zero w.r.t. the tail c/l) so that is unlikely to be the problem. As stated above, I have progressively moved the cg forward which appeared to be helping but I am not now quite so sure. It is way in front of where it should be. Never had this problem with a Spit. before and as you said, I am supposed to know what I am doing! Any further suggestions would be welcome.
Rather than remove lead I am seriously thinking of swapping the Laser 180 with the 155, which is lighter, in my Stampe. This would suit both models rather better but would involve a lot of work on each.
|Thread: Li`l Cub|
Don`t know what has happened here but I just replied to Steven and Denis. It has not appeared. OK, I shall do it again!
The wing was covered as normal then the slats, with their mounts fitted, were taped in place. I then drew round the mounts with a felt tip, removed the slats and put thin strips of masking tape round the marks. Covering then removed between the tape which was then also removed, slats re taped in place and thin Zap applied. R/C modeller`s glue to make sure. Not as bad as it may sound.
I would normally run these small four strokes on 10% but the 5 was in my box. My OS 26`s are happy on a 10x6 but I have added an extra head shim to them so that I can use up to a 12x5 on 20%. Next time out it will be a 9x5. The top end was sensitive on 5%. Rather than strip the carb. to see what the previous idiotic owner has done to it I shall wait and see since the 10% will require a richer mix anyway.
Glad I did not bother with them.
Hi both and thanks.
Steven, the wing was covered as normal first. I then attached the slats with tape with the mounts fitted to them and drew round on the LE with a felt tip. Slats removed and thin strips of masking tape applied round the ink marks. The covering was then cut off between these strips which were then removed. Slats then re taped on ensuring that they were level with the underside of the wing. A little thin Zap top and bottom to tack them in place then some r/c modeller`s glue to ensure a secure joint. Did not take as long to do as it may seem.
I used the 5% because that was what was in my bottle at the time but would normally use 10% on these small four strokes. The SC instructions say a 10x5 but since my 26`s are happy with 10x6`s I tested it with one. Will probably change this for the next flight since it did not seem very happy. The top end needle was sensitive which 10% will sort out. My OS motors have been fitted with an extra head shim to allow the use of up to a 12x5 on 20%. I shall strip down the carb to find out just what the previous idiotic owner has done to it. 10% fuel would need a richer mixture all round anyway so this may sort it without further attention.
Ran up the motor prior to a field visit. It was bought on ebay as supposedly bench run only and as new. Not so.
Everything which could possibly be tightened had been done with pliers, leaving lots of marks including each side of the carb. needle assembly, even the prop. driver. Crash damage to the carb. intake and mounting lugs. The prop. washer and nut were missing and it was covered in grass seed!
I ran it on Laser 5 fuel which should be OK. Not possible to lean out the mid range enough because the screw has bottomed out, but after fitting a new plug it is acceptable. Probably just a design fault on a budget motor.
Up at the field I range checked the untried gear and all was OK, so here we go. Take off was fine with less than full power but it violently veered off in a right roll and I only just had enough aileron authority to get it straight so carried on and landed at the far end of the field which luckily had the hay crop removed. It also tended to climb a lot and felt very stally.
On inspection the ailerons and flaps seemed to be drooping, despite careful setting up on the bench so I corrected this and added more throw with differential. I could see no warps so tried again, landing after a straight line flight. It was the wind sock which was telling porkies and wind under the left wing that caused the initial problems.
Went back up and flew round normally for a while, trying out the flaps at height. A few clicks of down were added. I felt that I was running out of up on the landing but too late to flick the rate switch.
Will increase the elevator throw for next time out. I use lots of expo so too much throw will not be a problem.
Power seems about right too.
I always like to take model home and check over everything after an initial flight so called it a day. Nothing else that I can think of to change so this should now be fine.
Question for Peter.
I have not fitted strut braces as yet. What are they for please?
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