DooMaw - building a STOL

[facthunter]

You have the long wait and the actual weight. How are they both working out? You are probably doing too good a job. Nev

 

 

[Head in the clouds]

You have the long wait and the actual weight. How are they both working out? You are probably doing too good a job. Nev

Hi FH, well the long wait is frustrating of course. The weight is always going to be more than we would like, and I'm a conservative calculator, so I'm sure there are a few kilos that a more determined Eng might be able to do away with. The wing and strut attachment are quite solid chunks of metal because of all the articulation required for the wing-folding method, and even more so because the struts still carry the full weight of the wings while folded and even while trailering though the wings will have some extra support for that. I'm willing to wear that extra weight for the convenience of a two minute folding system and the saving on hangar costs.

 

In flight the extra weight will be compensated for by huge slotted flaps which will keep the take-off and landing speeds quite low, even though the span is reasonably small (29ft) (130sq ft area). And the one positive about the extra weight is it should make the cruise more comfortable and increase the Va in turbulence.

 

I've lost track of what the actual weight will come out at but if it's not too much over 320kg I'll be happy enough.

 

Doing too good a job? I've usually found it takes me just as long to make a mess of something as to do it right - even not taking into account having to do it over again. Either way, I enjoy the flying most but the building is a pleasant hobby too, and the flying is certainly more relaxing when you know all the components are built right and will hold together ...

 

 

[facthunter]

You don't seem to be building your "average " Ultralight.... 320 Lbs will be a good effort if you achieve it but I don't recall what engine you are going for. I like a strong plane.. as you never know what load a bit of severe turbulence will put on it.. Over the years I've had a few experiences I don't care to repeat. where I thought the plane would break up. Nev

 

 

[Head in the clouds]

You don't seem to be building your "average " Ultralight.... 320 Lbs will be a good effort if you achieve it but I don't recall what engine you are going for. I like a strong plane.. as you never know what load a bit of severe turbulence will put on it.. Over the years I've had a few experiences I don't care to repeat. where I thought the plane would break up. Nev

320kg FH, not 320lbs ... even if it goes to 350kg I will still have a very useful payload at 600kg MTOW, but it looks like the weight increase might come through before I register it so I will probably build the spars for at least 6G yield at 750kg because at this stage all the rest of the airframe is good for way over 750kg MTOW, and the extra spar strength would permit fitting a much larger engine in the future.

 

The engine fitted now is a 100hp 912ULS.

 

I couldn't agree more about strong planes. It's all very well planning to be a fair weather flyer but it's the unexpected bad weather or mechanical turbulence or wake turbulence that can get you. I was doing a constant speed endorsement out of Coolangatta in the 1980s in glorious weather although with strong westerlies, when we hit a mountain wave that had both the instructor and me with significant head injuries and the instructor (a well known former RAF jet jockey) declared an inflight emergency with priority landing required. The plane was inspected and the mainspar of both wings was damaged with rivets torn out of the top skins.

 

Piper Arrow IIRC ...

 

And as for thermal/storm turbulence in the north in summer where I intend most of my flying again, well as you say "I like strong planes", and willing to add a little weight here and there to be happy and relaxed while just riding out the rough air when necessary.

 

 

[facthunter]

I meant 320 Kgs Sorry, (Trying to type too fast, and phone calls) Seems to be a "ball park" empty weight for a 2 seater . Good luck. with it. One of my BAD experiences was a standing wave downwind of a ridge.. We both hit the roof quite hard. enough to momentarily stun you. IF the seatbelts had not been very tight (as they were) It might have been pretty serious.. and we were expecting something to be there. Nev

 

 

[Marty_d]

More excellent work HITC!

 

You're so lucky I don't live near you - I'd always be after one more little welding job...

 

 

 

[Head in the clouds]

So - ten weeks ago I said I was back on the case, then I found that I simply couldn't do another thing at all because every square inch of the workbench was piled high with 'stuff', mostly bits and pieces left over and not sorted and put away from previously completed or partially completed parts of the project.

 

I started to make the instrument panel and drove myself mad because every time I put anything down I lost it among the other detritus on the bench, or I didn't have room to set up a jig or a hand-rest.

 

Consequently I embarked on a 'quick' clean-up, but I have this problem, with me it's all or nothing, so I ended up searching the net and travelling far and wide to get hold of as many steel 'Brownbuilt' style cabinets as I could ... oh, I forgot to mention we had a minor rodent plague here as well and they crapped all over the work I'd been doing and chewed some wiring and other bits I had to re-do so I also spent long hours buying and testing the whole gamut of rodent annihilation devices. For anyone who's curious - they all work but though some are better than others, you need all of them if you want to win.

 

We don't use poisons here because we have 4-500 birds that gather daily to amuse my good wife, and some of them would eat a dead or sick mouse and die as a result, and because of the birds and the occasional mouse we also have a number of friendly pythons and they might suffer a similar fate, and neither would I wish a nasty end on the two large eastern browns hanging here looking for a free feed, even the one which took a swipe at me a couple of weeks ago ... so it's all about trying to trap the wily (rodent) baskets - the ones the pythons and browns and kookaburras don't get, that is.

 

Best result so far has been with the 9000V rodent zapper, though any roach will also trigger it and it's therefore harmless until reset in the morning - the magpies love the zapped roaches. The Nooski seems like a lovely and easy trap concept but with two of them and three months has only produced one casualty so far. Snap traps are a waste of time here, the rodents' great grandparents have told millennium mouse all about how to raid them unscathed, and the self resetting box trap that will catch 'up to ten mice at a time' for release or drowning, hasn't caught anything except a very apologetic cane toad who had an irresistible urge to sample cat biscuits and dried baitfish.

 

The winner? The walk the plank and fall in a bucket thing. 

 

In the meantime I've been itching for much more flying the lovely little Kestrel. I've done lots of maintenance and replacing worn out things on it and it gets better and better, a few flights back I came home each time trailing long lengthens of gap strip (the fabric strips that close the gap between the wing trailing edge and the ailerons). It looked like a fair bit of hassle to replace them but I couldn't ignore the itch so ordered new fabric and the adhesive tapes and stitched them up and cleaned off the old adhesive and finally got it done - and wow, well I'd almost convinced myself it wasn't worth worrying about because the ailerons were so sluggish anyway ... but now the roll rate rivals anything I've flown, so I'm delighted. BUT - since then the weather has been totally crappy for weeks.

 

Okay, next post I'll tell something about the progress on DooMaw.

 

 

[Kyle Communications]

I know how you feel. I havent been back onto Mabel for months. Getting land bought and house built for the grand daughter and of course almost 4 weeks away in the USA and busy making ignition modules after I came back, took 3 days last weekend to do the rubber replacement in the girlfriend in that bloody heat. Oil pressure fluctuation problem before I went away I fixed just before I left. FINALLY this week back onto Mabel been doing works on the wing skins ready for alodining. So your not on your lonesome with distractions Alan ?

 

 

[Kyle Communications]

Oh the best mouse trap I have here is the garbage bin in my workshop. The mice get drawn here (because we have parrots here) and heaps of wild birds we feed. A old food wrapper or similar in the bottom of the big plastic bin literally every morning I come in there is 1 or 2 mice in the bin trying to jump out..they must do the big swan dive in there to get at the food then cant get out....works better than anything around here. Just need to leave the bin close to a shelf or something they can crawl on then they commit hari kari into the bin

 

 

[Blueadventures]

Hi HITC  Re walk the plank. Set up a wine bottle or long neck beer bottle horizontal with neck over the edge of a bucket. Smeer some cooking oil on neck and sick some bread crust in the end smeared with honey, syrup or peanut paste. Mice can't resist the lure and the bucket should fill in no time. No poison so can leave them out for the friendly wildlife to devour. If you try let me know what you think of the idea. It works foe us. Cheers  re wiring being eaten is it aviation grade wiring?

 

 

[Head in the clouds]

Hi HITC  Re walk the plank. Set up a wine bottle or long neck beer bottle horizontal with neck over the edge of a bucket. Smeer some cooking oil on neck and sick some bread crust in the end smeared with honey, syrup or peanut paste. Mice can't resist the lure and the bucket should fill in no time. No poison so can leave them out for the friendly wildlife to devour. If you try let me know what you think of the idea. It works foe us. Cheers  re wiring being eaten is it aviation grade wiring?

No, actually wiring of a test rig I had set up, and they chewed a lot of the exposed 240V wiring under the house as well ...

 

 

[Head in the clouds]

Another crappy weather day, 7am and gusting 20kts already, so regardless that it's Saturday and the club Christmas BBQ is at lunchtime, the Kestrel will be staying in its trailer yet again. It does handle the strong winds quite well, my flight before last was in 25kts, gusting 35kts and it was all quite controllable, which is pretty good for a 150kg ultralight, but at 55kts cruise it's a long time getting anywhere, or back, depending whether 'anywhere' is into wind or downwind ... It's not even that, so much, but with the light wing-loading it can be quite a rough ride and that takes a lot of the fun out of it.

 

Anyway, it's probably a good thing, if the weather was always nice I'd be flying a lot more, but there would be even less progress on DooMaw.

 

So - having had the big tidy-up and all the various half-done parts of the project have their own project box on its own shelf in the relevant steel cabinet among the line of steel cabinets (oh, joy, I can find everything in an instant now), so it's time to get back to productive work.

 

Here is what I think of as rather an historic photo of the work-bench - taken yesterday, and historic because it's ancient times since the bench was last completely clear -

 

 

Right now there is just one thing on the whole work-bench, so even I can't confuse myself and start wondering what I was working on last! Here is a photo -

 

 

That is how far I got with building the instrument panel about two months ago. The instrument positioning looks a bit unconventional because they have to be located where they won't clash with the truss which resolves the landing gear loads, which is directly behind the panel. There's only about 3mm clearance around each instrument, so they have to be placed quite accurately, especially since the panel is rubber mounted, though it doesn't move more than about 1-2mm each way. Down the track I will invest in a pair of MGL digital instruments and do away with most of the steam gauges but for the moment, due to their $6-7k price, they will have to stay on the wish-list.

 

The angled flat portion of the panel is for a nav tablet and the pieces sticking up will be folded over and trimmed, to hold the tablet in place. Next stage is to make up the parts to complete the flanges at the corners and weld them in - I suppose I can still remember how to weld ...

 

 

[apm]

I have MGL instruments and like them, but Oleg’s setup is the way to go. Muct better value for money, pretty easy to put together, He gave a really good presentation on this at Ausfly Narromine in October.

 

 

Home - Experimental Avionics

 

EXPERIMENTALAVIONICS.COM

 

DIY avionics for Experimental Aircrafts. Aviation related electronics projects based on modern microprocessors, micro-controllers and solid state sensors.

 

 

[rgmwa]

QwikEFIS might be worth considering. http://members.iinet.net.au/~ninelima/efis/index.html

 

I have no connection with the author and don't use it personally, but it looks like good piece of software for Android devices.

 

 

[Head in the clouds]

I have MGL instruments and like them, but Oleg’s setup is the way to go. Muct better value for money, pretty easy to put together, He gave a really good presentation on this at Ausfly Narromine in October.

 

 

Home - Experimental Avionics

 

EXPERIMENTALAVIONICS.COM

 

DIY avionics for Experimental Aircrafts. Aviation related electronics projects based on modern microprocessors, micro-controllers and solid state sensors.

 

 

QwikEFIS might be worth considering. http://members.iinet.net.au/~ninelima/efis/index.html

I have no connection with the author and don't use it personally, but it looks like good piece of software for Android devices.

 

Many thanks apm and rgmwa! I'd seen Oleg's thing before and completely forgotten about it, and QwikEFIS is new to me, so I'll have a good look at both and see where we go from there.

 

Are there any more like this out there that I should be considering?

 

 

[Subsonic]

A very interesting build this one, which I have been following for a while.  Have you made any further progress?

 

Michael.