Dave Brooks
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Posts posted by Dave Brooks
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Dear Andy / ED,
Thanks very much for the useful advice. Yes, it bolts on from the muffler side and is an early example (ringed piston I think). I'll go for a 6-32 UNC which seem to be available and is very close to what I've measured. I could re-tap the holes but would rather reserve this option in case it's absolutely necessary as the threads are part of the main casting.
Many thanks indeed.
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Hi all,
I'm after a bit of advice please. I have an older Irvine 61 engine (silver casing) and am making an extension piece for the muffler, necessitating some longer bolts. Measuring the existing ones, they don't seem to be a metric size. Would these be imperial? I measure them at 3.33mm diameter which is slightly bigger than 1/8 inch. Is anyone familiar with these engines and would be able to advise on what threads I need please? Many thanks.
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I would second a DC Merlin. I have one in a Tomboy and its ideal. If you want a new engine then a PAW 049 or 06 are just about the only option. Great British engines and available with a throttle!
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Have you tried Just Engines for Perry pumps? I got one from them about 18 months ago. 2stroke and 4stroke versions available.
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Many thanks for the information. Lesson learned. Might also be a comparatively safe way to discharge old lipo batteries prior to disposal I suppose! Thanks also for the digiswitch recommendation. These do look good but at c.£45 a time are probably beyond the reserve of most of my airframes.
Assistance much appreciated.
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Hi all,
Just after a little advice on this topic please. I tried using a 2s 1000mah Lipo with a small UBEC as an alternative RX power source, however, I think I made a mistake in that when disconnecting the the battery from the plane I left it attached to the UBEC. After a week or so, when I came to check the battery it was completely drained and not recoverable. This happened on two occasions, ruining two separate lipos (the first time I assumed the battery had failed for other reasons). I assumed that as there was no current draw it wouldn't matter if the UBEC remained attached to the battery but perhaps this isn't the case and the UBEC circuit continues to drain the battery over time. Has anyone else experienced similar? Thanks
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Sad news for we engine appreciators but nothing stays the same forever. Very best of luck in the new career Jon. I have a rather modest pair of laser 70s but they are certainly cherished and will be even more so now.
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Specs including recommended props and other instructions are available on PAWs website but if you want a simple recommendation I use 10 x 4 props on my PAW 19s in similar models and they work well.
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These have higher compression compared to glow and I'd be surprised if you could turn it over without a prop on! I wouldn't screw the comp in any further but you won't do any harm by unscrewing it. I'd leave it exactly where it is as there is a chance its at its last good running setting and if so will save a lot of grief trying to get close again, especially if you're new to diesels. Instructions usually tell you to increase compression from running setting a little for starting but none of my engines are exactly the same. Some like to be slightly under and some slightly over. I think you have to learn the feel of each engine, which is of course part of the fun! Tuning requires balancing compression and fuel mixture so is an iterative process.
It probably took me 2 or 3 sessions of several hours each and a very worn out arm to get my first diesel running and learn the necessary 'flick' technique. Perseverance (or sheer refusal to be beaten) is the key!
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Nice engine. Good choice Sir!
I can recommend the Vic Smeed 'Electra' as a suitable airframe. Plans available for free on outerzone. So named I think because it was designed as very early single channel R/C model, nothing to do with electric power! Its large and light enough to fly slowly and is an inherently stable free flight type design. I chose this for an early build as it uses sheet sides so a lot less framework to build compared to many similar models. I simplified it further by building a flat horizontal stabiliser and it doesn't seem to have compromised its flying characteristics at all.
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I don't know if its any help or whether it will make any sense but I recently managed to turn a tapered collet and matching internal taper in a prop driver on the ML4. I used an end mill clamped in the toolpost as a boring bar. The end mill had the same diameter as the small end of the internal taper and gives you necessary clearance all round. Taking things very slowly and in Aluminium this worked well. If you have a compound slide (which I think you do?) as long as you don't move it at any point between doing the external and internal tapers then they should match exactly. One benefit of the original tool post on the ML4 is the ability to clamp various different things and your Drummond is probably similar. To clamp the end mill I made a very simple, small aluminium 'v' block and the shimmed it and rotated the end mill to get one of the mill cutting flutes on centre. I did this with an 8mm end mill.
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Engine prices on ebay remain surprisingly strong, especially for decent examples. Perhaps because there aren't that many new options? Much cheaper in person at a swapmeet if you can find one locally or ask around at the local club as someone will have some squirreled away!
I am a fan of diesels for vintage type models. You will need to acquire the 'knack' but once you've got it the mechanical elegance is appealing. The smell and mess you will either love or hate. As objet d'arte they are much nicer than glow engines in my opinion and a more fitting pace/sound in a vintage type. This PAW19 flies my 52" Vic Smeed 'Electra' easily on just above tickover for beautifully relaxed flying. Its reasonably similar to a Junior 60. I have 3 PAW 19s in different models including the semi-scale 42" SE5. All are excellent runners and superbly engineered. Not super cheap but you can still buy them directly from PAW and support one of the few remaining UK manufacturers of such wonderful things. Worth every penny!
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Looks as though you're making good progress. Its easy to get frustrated, especially using less than perfect tools, but as you've said yourself, that's partly what this project is about. Its looks easy to do this on an high end machine with perfect rigid set up, but how many have that luxury? Even if you'd ruined that part, you've clearly learned enough to have a better chance of success next time round.
I quite like that if something doesn't go entirely to plan on my small old lathe, typically the drive belt just slips without too much further drama! I think that back in the day these machines could be powered by a treadle arrangement which looks fun and might provide some variable speed capability! The idea of machining with no mechanical assistance does appeal rather. I think my approach is similar to yours in that on an old machine with no gradations you have to proceed by 'feel' to some degree and understand what the machine is capable of for different materials and cuts etc.
I'm learning much here and am in danger of being inspired to have a go too. I've been looking at the Boll Aero 18 and have most of the materials ready to go but not quite the confidence that I can achieve the required accuracy with my set up just yet! Looking forward to seeing how you tackle the piston/bore elements!
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I'm really enjoying following this build and the wonderful lathe! I have a pre-war Myford ML4 which I am getting to grips with. Great to see what can be achieved and I'm looking forward to seeing the outcome of this project. Keep up the good work!
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11 hours ago, Chris Freeman 3 said:
We under estimate the speed that our aircraft fly, especially over longer distances. I found the old article on our flight and that should give more detail on the challenges of a flight like this.robbin Island.pdf
Thanks Chris, I enjoyed reading about this. Did you all manage to hold on to your breakfast!
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If its not designed to be changed between modes then I'd be very careful. Other functions such as rates, mixes, throttle cuts and potentially failsafe settings could stay with the original channels leading to potentially unexpected or even dangerous results. The manual should indicate whether it is mode changeable.
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Yes indeed, would need to factor in the support vessel and avoid getting squashed by cargo ships etc. Getting the airframe there in the first place, permission to use airspace close to the airport. The more I think about it the actual flying is probably the easy part!
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Thanks ever so much, that is exactly the information I was after. Brilliant! I'm hoping to give this T180 a new lease of life and perhaps even use it as a club trainer and to offer some trial flights via the buddy box. It should be suitably stable and robust for this type of thing. It came with a lovely SC52FS engine which looks to be in good condition now I've unglued the carburettor. I doubt it will get as far as Robben Island however. That sounds like an interesting story? Got me thinking though......I regularly visit Gibraltar and I wonder if anyone has ever crossed the straight to Morocco by radio control? Perhaps the best chance of a transcontinental flight! Its only 8 miles so someone must have done it. How big a tank would I need for that distance.............
Thanks again for the info, very much appreciated.
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Thanks Geoff.
38p! Those were clearly the days. Current balsa prices are one of the reasons I now prefer to refurbish old airframes rather than build from scratch. The raw materials would have cost way more than the completed airframe second hand.
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Hello everyone. Could anyone with experience of the Precedent T180 advise on a recommended CoG please? I have just aquired an example which will require a little recommissioning before I can get it back in the air but I don't know where the balance point should be. It looks as though it has a lifting tailplane section.
Many thanks indeed.
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Thank you. I'll have a look. I have one of the older lightweight 6 channel RXs from lemon and never had any issues with that one so I'm happy enough to give the newer version a try.
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Hi Toto,
If you don't mind my asking, where are you purchasing your lemon receivers from please? I could do with couple too!
Many thanks,
Dave
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Caveman explains this better than I did. There are 2 mixes available in aeroplane mode (called acro on the dx6i) although I can't remember whether these are in the setup or adjust menu without my Tx to hand. You need to enable one of them in programming menu to mix aileron and rudder 100% in both directions. If your microaces plane has a micro 'all in one' type receiver and linear servo setup then you can't unplug the leads to swap channels on the receiver.
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Hi David,
I'm afraid I don't know about the switch although I think they can be a weak point.
With regard to the channels and sticks, there isn't (as far as I am aware) a way to reassign channels on the dx6i (if you can't swap the servo leads in the receiver). I get around this on my 3 channel planes by adding a 100% mix between the rudder and aileron channels. That way both sticks control the rudder. You could disable the LHS stick by setting rates to 0 just for the rudder channel but I find its handy to keep it if you are used to using rudder so steer on the ground. In addition, using both inputs together gives you additional throw if you need it.
I hope this makes some sense!
Dave
Three channel stabiliser with Rudder(not Ailerons.)
in All Things Model Flying
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Not claiming to be a great expert but I do use basic 3 axis gyros on some of my planes. Roll and yaw are inherently linked in a rudder only situation so you only have one control surface to move to correct any deviation caused by external forces. I would suggest that what you want the gyro to do primarily is to keep the wings level, in which case, route the rudder control through the aileron channel which will then sense roll and apply opposite rudder to correct accordingly. The roll movement will probably be more pronounced than associated yaw and consequently be easier for the gyro to detect and respond to. The necessary inputs will also remain the same irrespective of which way up the model is, which may not be true for yaw. The yaw will probably be more subtle and less directly connected to the current orientation of the wings. I would also then mix in control via the rudder stick on the transmitter as suggested.