pylon500

Just for interest; <https://plus.google.com/photos/113292981019876413104/albums/5573889605855816225?banner=pwa>

There is possibly two fronts to look at this. When you talk torque curves for engines, the reason they drop off near the top is usually caused by the engines inability to continue breathing and porting at higher RPMs, unless it's turbo'ed, and eventually even that ratio will give up. The other factor is as mentioned, that the prop is stalling near the root (while static) because of the high pitch inboard. Really high pitch props can stall, cavitate, FLUTTER while static, if you can get enough torque 'up' them! I've heard flutter a few times over the years, typically on VW and Jabiru engines running small diameter, high pitch props. I've also heard it when not so clever people have put props on backwards!! yes it happens. RickH, the prop size thing is to do with the operating RPM's of the different engine/reduction systems. A 503 at 6800 with a 3:1 C box has the prop turning at 2266 RPM, a Jab (which is direct drive) needs to run to 3300 RPM to put out any power, so the prop diameter needs to come down to stay sub-sonic.

Always a shame to loose a fellow pilot, let alone a fellow Lightwing pilot. Not 100% sure, but would this be the first fatality in a Lightwing in their 28+ years of operation? Will wait to find out what happened... Condolences to family.

I'm not sure which branch of the Gestapo you're worried about, but I'm fairly sure the printed copy should suffice, as this gives traceability to the real registration. Maybe a copy of the receipt as well...?

G'Day Nunans, yeah, there's a few assorted things going on there.... Most GR-912's tend to run nose heavy, and part of the original design philosophy was to limit the elevator travel, hoping to create a 'mush' instead of a full stall. Unfortunately this mush develops into around about an 800 fpm (or higher) decent rate, not the sort of rate you want to contact the ground at ! Elevator gap seals here are important. As a side line, I should point out that aileron gap seals are MANDATORY on a Lightwing, it flies really badly without them. There is also another problem that is not spoken about much, or totally proven/disproven, that deals with the shape of the cabin roof, and the airflow it causes over the tail at high angles (flaring) of attack. Depending on the fit of the gap seals and number of antennae in the cabin roof, it is suspected that during flare, airflow over the cabin prematurely separates causing a drop in elevator response as well as triggering an earlier onset of stall, ending up with your 'drop on' effect. I may sound vague here about a definite tendency because, of the 9 Lightwings I've flown, only 3 of them did this noticeably, the rest were fairly docile. The GR 582's are easier to flare and land (at idle) as they are lighter and have the undercarriage in the right place (it's a long thread, but I explain that statement here; http://www.recreationalflying.com/threads/the-lightwing-mystery.6696/page-2#post-235738). The GR-912's with the U/C further forward prefer to be 'three pointed' as they are easy to bounce, BUT some GR-912's can be wheeled on as easily as the two strokes?? All my landings are based on dead idle, full glide approaches, anything is easier to land with a bit of power, but one day you may not have it.......

If you are running the 3:1 C box on a 582, a 66x44 would probably be a bit under propped. 66 x 42 or 44 is more typical of a 582 with a 2.85:1 B box. Given the choice, I would choose the 3 blade Bolly and they are on special at the moment in the magazine. Interestingly, the prop on the manual looks like a GSC (Canadian) prop, just like was supplied with our GR582 after one of it's overhauls at Howie's Just remember NOT to use the oil stated in the manual (obviously a typo), keep using two stroke oil.

I feel that very few of the mass produced props out there that we use are actually 'Certified'. Sure many of them have been well 'tested', and the odd one or two have come up wanting, but on the whole they all work, just some better than others. The talk of just dropping a 24-, 55-, 24- aircraft to a 19- is pointless. As said, most of the aircraft here with problems are older models that have worn out their props, or the owner/operators have decided to fit a more efficient, economical, quieter prop. Not to beat around the bush, but anyone that flies a Skyfox/Gazelle will tell you the original 'lump of wood' can be well out classed by even a Brolga. Many people building 19- Jabiru powered aircraft will opt for the Sensenich prop, if they can afford it. Aeroprakt could not guarantee supply of the Kiev props, so approved Warp Drives, many now think the Foxbat performs better with the Warp..... As I said before, this is blowing out of proportion. What we really need (with our 10,000 members) is to get another exemption (for ALL ultralights) regarding the technical status of the propellors we use. As a side question, how many actually use 'aircraft' grade tires on their planes?

This has been a problem for a long time, ask anyone with a Skyfox/Gazelle. Obviously all our rules are just variations of CASA's, and the GA world with it's low rpm, high torque engines has many problems with it's usually heavy propellors. The reality is, as I see it, is that a propellor on a plane, is like a tire on a car. It is the prime motive force for the vehicle, so as long as we fit the right diameter and width, regardless of the manufacturer, the police are happy. If someone builds their own aircraft, they can optimise the prop to suit their performance and budget. Manufacturers however, tend to look more at the budget (profit margin) and often select a cheaper (or home made) prop. Unfortunately the aircraft then gets 'certified' with this average prop, and we all suffer. What we should be doing is getting RAAus to lobby back at CASA, and have the requirements for propellors removed from the certification process. I mean, no one worries about which brand of tires you fit to your aircraft, many people change over to decent radios, many people have their own ideas on which oils to use, short people situ on non certified cushions, etc, etc. If we get stuck with the 'every certified nut and bolt' system that GA suffers, then we've basically lost the game. As for the Lighting, Howie has supplied aircraft with GSC props, Catto props, 'Home Brand' pieces of wood (not worth calling props) and Bolly props, from the factory. I know of MANY Lightwings that have had Brolga and Warp Drive props, and really, we should be able to get these approved simply through proof of safe history of operation over the years, without having to go the route of Reg 35 engineers signing them off. This latest witch hunt has the threat of grounding a huge number of 'slightly improved' aircraft, that have been flying safely this way for years.

Nah ,just a Rans S-7, but I'm not sure what engine he has in it, almost sounds like a two stroke? OK, just found another video, and it shows a Rotax 912S... with three blade Warp Drive.

Some clues when looking at the aircraft, no dihedral and a lot of camber on lower wing battens, to give a semi symmetrical section. Hope he has a STRONG kingpost!

Unless there were 'follow on' changes between the GA-55 and the GA-912, the wing tank details should be similar. Many of the GA-55's were kit built, usually registered 28-XXXX, so there should be some plans out there somewhere? For those following and wanting to know the Lightwing series a little better, I had a post a few years back describing the variations; http://www.recreationalflying.com/threads/thoughts-on-lightwing-mark-2-version.49/#post-368 The GA-912S should be the ultimate Lightwing, pity it was never certified and put into production......

When one of my 'fleet' was grounded about mid November, things looked dire. Added to the fact the aircraft is owned by one of my students, so the paperwork has to get to him, he has to find time to get it to me, I've got to go through and follow the new (2007?) compliances, (photos of MTOW and 'unsafe aircraft' placards), tally the hours and landings, send it back to the owner for him to add his payment, then wait for him to forward it back to RAAus. Having said all that, the office phoned the owner yesterday to tell him the aircraft is now registered, and he will receive the paperwork shortly. Yay, I get to have an aircraft for the Christmas break.

"But I'm not dead yet!" Monty Python.....

'I didn't want to reply' You will note I have not mentioned any names, probably because I know of a few! I've been around.........

It's unfortunate that the financial investment in building your own aircraft is such that it's hard to say; "Well, I've learnt a lot building that, I've also learnt that what I've built is rubbish, so I will have another go and get it right" By the same token, by the time many people have 'finished' a homebuilt, they have usually made enough parts (and thrown them out) to built two and a half planes! Welcome to the learning process. What worries me more than someone who eventually finishes and flies their first aircraft, are the ones that then go on and think; "That was easy. Now I will modify it, and go into production, and sell them" not realising that if it was easy, it was because the original designer put a lot of thought into the aerodynamics, engineering, plans and parts, and a manual to help beginners put it together. The better designers usually have a background of working their way up through the aviation industry, to avoid having to learn by their own mistakes.

Simple answer is 'All movement is around the Centre of Gravity' But remember, the centre of gravity, or balance point, exists in 3 directions (axis).

Looks like about a 10m x 10m, and paid $30k? I guess it's a case of available money but a 10m x 20m would be a lot less than $60k, and you could rent 2 spaces....? I built 18m x 24m (plus office annexe) and cost me about $65k 'cause I wanted to collect ultralights, and I did... Mostly other peoples' Only took 12 months to go from; I really wanted two hangars, but council stuffed that up!

Personally I would stay away from hoping to achieve LSA status. That said, if this is 472kg MTOW, it fits 19-xxxx. Not sure why people want to build/fly 'Walter Mitty' machines like this, and carry passengers? I figure, if you want a two seater, build a two seater Just me photoshopping again although some of my initial drawings here; https://plus.google.com/photos/113292981019876413104/albums/5212775815502683841/5424354393046479058?banner=pwa

Was required to send photographic evidence of MTOW and 'Unsafe Aircraft' placards on instrument panel. Supplied on 07/12/12. Nothing yet........ Should point out that in the past, when doing a new rego (the above is not) you were supplied with an 'Unsafe Aircraft' sticker and told to affix prominently. No mention was made with regards to photographing said placard (or others required placards), and sending in to complete rego. The inspector merely needed to observe the owner sign the form, that said placards were in place......

Video #2 & 3 are typical two stroke failures, reasonably abrupt and total. Not sure what's going on with the engine in video #1, it loses power, but sounds to be running all the way to the ground? Maybe not a two stroke? As for the impact, he probably got caught by windshear down between the trees. Will Cathy ever talk to him again??! That look, OUCH.

I started doing some drawings for something a bit bigger, but I don't see myself having any time to do anything in the foreseeable future:no: As for the photo, unfortunately yes, photoshop. Just trying to inspire myself while playing with CAD Truth is, (and looking at your avatar) I am more likely to build the Hurricane I started drawing a few years back. https://plus.google.com/photos/113292981019876413104/albums/5212775815502683841/5315228105331359986?banner=pwa

It used to be the norm, and taught by instructors, until the Human Factor thing came in. Now, as long as we've had a good nights sleep, and haven't been smoking too much and can make psychobabble quotes, pilots can do pretty much what they want....

Mustangs, mustangs, mustangs everywhere! Seems there's a good choice of scaled mustangs available now (working up from small); W.A.R. Mustang 53% http://www.waraircraftreplicas.com/ Falconaravia P51 66% http://www.falconaravia.com/ F.E.W. Mustang 66% http://groups.yahoo.com/group/FEWbuilders/ Stuart Mustang 70% http://www.seas.ucla.edu/~osmith/s51/ Thunder Mustang 74% http://en.wikipedia.org/wiki/Papa_51_Thunder_Mustang Loehle 5151 75% http://www.loehle.com/MustangKit.htm Titan 51B & D 75% http://www.titanaircraft.com/t-51d.php Jurca Mustang 77% http://www.marcel-jurca.com/index.php?option=com_content&view=article&id=191&Itemid=238&lang=en And the latest offering, from Germany; Scalewings FK 51 70% http://www.scalewings.com/mu%20specifications%20englisch.htm There are also a couple of places set up to make 100% replicas of p51D and B models. Don't think anyone has done a Hawker Tempest yet.....

As mentioned earlier, different carbi installations can have different effects. If not using the pre-carb plenum chamber, I think Rotax supplies small springs and tabs to support the weight of the carbi across the manifold rubber. I have seen older carbi rubbers cause leakage as the steel mounting plate moulded within starts to rust.

OK, I see where you are coming from. The nearest we (ultralights) get is more like 'Approved' in the 19-xxxx class. Hopefully, these are L-4's and or LAME's, but I put to you an interesting observation, having worked in GA for nearly 30 years... The people with the most knowledge of aircraft design, ie Reg35 Aeronautical Engineers, very rarely actually build their own aircraft !?