rake vs dropped keel

[WHY]

Having watched closely the development of the gyro that N. Karaolides (Aviomania) has done in Cyprus and seen the end results, I wonder why more of the "raked keel" designs are not seen as opposed to the "dropped Keel) version. It appears to give a better aerodynamic profile of the pilot (slightly) reclined as opposed to the "kitchen chair" seating with most dropped keel design. Is the raked keel design more difficult to build or more expensive to build or is it just that it takes time for a mind set to change. And as for a ultralight design, I don't know how you can beat Chuck"s design but no one seems to have picked up on it ??????

Anyone want to venture some guesses ?

Tony

[Friendly]

Tony,
I for one like the raked keel, ever since I saw it on the MTO3 . There are a lot of Bensens and Brocks that came with the Mac out there. the drop keel is the most cost effective way to add a prop larger than 52inches to the existing gyro. It only requires the keel to be cut into without changing any holes, only the cluster plates and adding the holes to the bottom of the cluster plate and the rear keel. The seat and controls all remain intack and the nose wheel is extended. I have been talking with some friends in our club and a few people I met here on the forum. I think my next gyro will be a "Bensen Xtream" which will be a slanted or raked keel. It just takes time and money.

[WHY]

Hi Mark

I see your point on the ''easist way to convert to a longer prop". I saw a couple of "pods" for sale earlier, I think were priced at $250, looked like they were custom designed for a raked keel, looks like even a pod from a fixed wing Quicksilver might work well, as always, less drag equals more performance.

Tony

[Lee Scatt]

Check out the MisFit build. Raked keel, beam axle. Maybe CLT? Hacksaw and a drill.

[Earthboundmisft]

I beg you pardon, CHOPSAW my good friend. Aint it purdeee, hehehe...

[Passin' Thru]

Check out the MisFit build. Raked keel, beam axle. Maybe CLT? Hacksaw and a drill

When ya'll gonna fly that lil' jewel????

[Earthboundmisft]

Hey Pete, THANKS! that means a lot! I still need to learn to fly. I have reworked the nosewheel, much more robust now! Stay tuned....

[Friendly]

Do you have a link to your build? I am computer ill litter rat.

[birdy]

It appears to give a better aerodynamic profile of the pilot (slightly) reclined as opposed to the "kitchen chair" seating with most dropped keel design.
I flew on of them slopen seated things once [ Mitchs butterfly] and kept slipn forward.
A square uprite seat is best if your go'n to throw it about abit, or if your go'n to be init till the fuel runs out. [ 5 hours]

[Greg Mitchell]

http://www.youtube.com/watch?v=TG2yOn5XNzc

[Resasi]

Birdy, now that's being agricultural/practical, got to know people like sexy even if they do slide forwards all the time.

Just kidding guys. I know the F16 jocks are semi-reclined and that is an orgasmic looking machine. But then they do pull some serious G's and that happens to be a good position for that horsing around.

That new gyro in Austria looks great but if I spent any amount of time like that I would probably go to sleep. If... I could sleep after spending that much cash on it. That is the super sports car of the gyro world

Nicolas's machine does look good and I know that he is making serious efforts to get it out on the market. I look forward to seeing some of those flying as both the single and the dual version look like a really nice flying machines.

As for MisFit. That is a seriously pretty little jewel. Beautiful build. My son and I really did admire that at B days. Enjoyed the tail art as well, cheeky isn't she.;)

[SnoBird]

Here's the original rake keel machine...
http://i289.photobucket.com/albums/ll224/my-pics-are-here/KWTaxiBack.jpg
http://i289.photobucket.com/albums/ll224/my-pics-are-here/KWTakeoff.jpg

[Resasi]

Now that is shirtsleeve flying.

No helmet, but I did note that the gentleman was wearing a tie.

Bit then again one would expect that from a Wing Commander after all.

[SnoBird]

Ken Wallis is so bad ass he don't need no stinkin' helmet. :D

[Gyro_Kai]

It appears to give a better aerodynamic profile of the pilot (slightly) reclined as opposed to the "kitchen chair" seating with most dropped keel design.
I flew on of them slopen seated things once [ Mitchs butterfly] and kept slipn forward.
A square uprite seat is best if your go'n to throw it about abit, or if your go'n to be init till the fuel runs out. [ 5 hours]

Birdy, simply reclining the back-rest doesn't do it. Additionally also the seat must tilt backwards. Then you are fixed in the seat like a baby in in a Maxi-Cosy :D

Downside is, that visibility is somewhat obstructed.

Kai.

[C. Beaty]

Pilots of high performance sailplanes are almost flat on their backs and manage to tolerate many hours in that position during contests. A sailplane wouldn’t be high performance with kitchen chair seat.

Jet fighter pilots are in a semi-reclining position because the body can better tolerate “G” forces in that position. Blood stays in their heads instead of going to their feet.

Uncomfortable seats can be designed whether upright or reclining.

[Vance]

I found in my motorcycle streamliner that the extremely supine seating made it more difficult to sense lean and I had to become more visual for the clues as to my angle of bank.

I felt it was because my head moved relatively less as the motorcycle banked compared to a more upright motorcycle streamliner that I had ridden.

My head was about 6 inches above the vertical center of gravity. The other Streamliner had my head almost 18 inches above the vertical center of gravity. A typical motorcycle might have my head 36 inches above the tire contact patch.

As I write this I wonder if an aircraft with the pilots head closer to the vertical center of gravity would make it harder to sense bank.

I remember feeling somewhat lost in the Snowbird as compared to the Predator or the SparrowHawk. At the time I felt it was because of less visual reference with the Snow Bird. I feel that my head is much closer to the vertical center of gravity in the Snow Bird and therefore moves in less of an arc as the aircraft rolls.

I may have had a similar experience in a Magni as I touched down the left main before the right.

I would be grateful for other pilot’s sharing their antidotal experience with this.

Thank you, Vance

[dinoa]

The reclining position in sailplanes is so comfortable it often induces sleep especially up high were the air is thin.

The only detriment I see is losing some visibility directly ahead and below. No big deal.

Dino

[Earthboundmisft]

I raced on asphalt ovals, twice a week for 3 years. My personal preferance, was a very upright seating arrangement, much like a sprintcar. I think it helped with my sucess, as many other drivers were noticably reclined, Earnhardt style. I could 'feel' the car better.
Gyros might be the same deal...

[birdy]

Downside is, that visibility is somewhat obstructed.
Thats the first thing i thought in Mitchs machine.
" bloobyell, id look like a frign hunchback after a day lookn for moos in this thing"
Sorry Mitch, didnt i mention that? ;)

[WHY]

Well it seems pretty well established that the determining factor as to whether you would want reclining or kitchen chair is going to be "how you intend to use it " have a crop duster in hangar next to me and was making a note of his seating, not only is he in the kitchen chair but setting up high. obviously vision is king in this application and he has 750 hp out front in a turboprop for performance which helps to overcome the drag of the design and all of the spray rigging.

Now if your looking for some performance/efficiency then I think drag reduction is the first place to look. I have often wondered if a lb of weight takes as much power as a pound of drag at a given speed, because if I remember right a pound of drag goes up by the square as speed doubles, so the comparison would have to be at a given speed.

Tony

[WHY]

When it comes to simplicity I do not think it is possible to beat Igor Bensen's design, I do think though that the raked keel is a considerable design improvement and for only a"little more money and a little more work",a noticable improvement can be seen in performance with the same hp, since the pilot is not quite such an "airbrake"

Tony

[dinoa]

Tony,

Extra weight divided by the L/D (Lift /Drag) or glide ratio of the machine would be the extra thrust needed to carry that weight. Lets say because the machine is clean the L/D is 5 so carrying an extra pound would need 0.2 lbs extra thrust from the prop at its best glide speed.

Dino

[phantom]

it took me a while to get my head around the term and I thought there was some new type of gyro out there that I had never seen but then I realized that I have one but for years I have been calling mine a cranked keel and I have told people that the reason that more aren't built like mine is because it is harder to get in and out of due to the high seat but then dropped keel machines came out and they have seats as high as mine and people build them so now I tell every one that it isn't copyed because it's just ugly.

[karlbamforth]

it took me a while to get my head around the term and I thought there was some new type of gyro out there that I had never seen but then I realized that I have one but for years I have been calling mine a cranked keel and I have told people that the reason that more aren't built like mine is because it is harder to get in and out of due to the high seat but then dropped keel machines came out and they have seats as high as mine and people build them so now I tell every one that it isn't copyed because it's just ugly.

I took "raked" to be more like the Wallis gyro see pic in post 12.

Maybe we need it better defined.

Looking at the pics in post 12 the Wallis gyro appears (yes I know looks doesn't make it so) to be close to CLT. If it is then Cmdr Wallis gyro's must be the smallest, lowest profile near CLT machines around. This probably accounts for the good altitude and speed performance that he gets.

[WHY]

Hi Karl

Yes that is what I meant by "raked keel". I think Aviomania in Cyprus just improved on it a "little" when he "flattened" out the tail angle.

Tony

[WHY]

Karl, a PS to post #26, With no HS you can bet your shirt that is a CLT gyro.

Tony

[SnoBird]

I took "raked" to be more like the Wallis gyro see pic in post 12. Maybe we need it better defined. Looking at the pics in post 12 the Wallis gyro appears (yes I know looks doesn't make it so) to be close to CLT. If it is then Cmdr Wallis gyro's must be the smallest, lowest profile near CLT machines around. This probably accounts for the good altitude and speed performance that he gets.

I agree that Wallis' machine likely is very close to centerline thrust, and I also believe the center of pressure is pretty close to the CG as well. He knew that keeping the pilot's weight higher (via quasi-supine seated rake keel) enhanced stability. He kept his machine very compact and structurally efficient, minimizing weight and avoiding the insidious growth/weight endemic with machines that use large, gear reduced props. Yet still included niceties like a tidy incorporated prerotator, half-shell enclosures and semi-suspension landing gear (never mind the machine guns, aerial mines and flamethrowers :)). Chuck B has also suggested his wood blades may be overbalanced in a way that enhances stability. I mean when you really start to look at this 50+ year old design, you can see the old man knew exactly what he was doing many, many years ago long before anyone else did (with Igor Bensen as a possible exception). He's simply brilliant, his machines and his amazing accomplishments prove it conclusively and speak for themselves.

[WHY]

I think in some other threads, Aviomania in Cyprus mentioned that they were going to possibly offer some kits later (I hope I hope I hope) and maybe some plans for their great little gyro. But wonder has anyone else in the past offered any plans for a raked keel design gyro, especially using a combination of square tubing and round tubing and a articulated gear?????

I realize that many are reluctant to go out a build a design from scratch and this is probably a good thing in more ways than one, but I also think if a good set of plans for a raked keel design were offered or made available( especially one that has been flown and proven) they would be really sought after. Although my preference for a design is a tractor, I think the raked keel is the next major step up from basic Bensen design, of course the Dominator is in a design class all it's own and has proven it's self beyond question.

Tony

[Passin' Thru]

Tony, I thought Nicolas was going to offer plans for his machine, but so far ...?
Are you famialiar with Jukka Tervamaki's JT-5 ? It's been around for quite a while, but it is not a simple bolt togather design.
http://www.icon.fi/~jtki/jt5gyroplan.html

[WHY]

Hi Pete

Yes, I am familiar with Jukka's JT-5. I had the extremely good fortune to hear Jukka speak at the seminar held by Dr. Bruce Charnov at Hoffstra University a few years ago. Mr Tervamaki is a very facinating person.

It sure would be nice if Nicolas comes out with those plans, it would also be great if he could be a guest speaker at Mentone National next year ????????????????? Maybe by that time someone would have one of his kits at Mentone to show????????????

Well, one can dream can't one?

Tony

[Aviomania]

Tony, Pete,

Plans and kits ARE available (1 is already shipped, 1 will be shipped in few days and we are talking for 3 more...... none yet to the USA).

I am not offering it ONLY as plan because my experience in the gyro community showed that a lot of people are "cutting corners".... since i want my gyro to built as designed and proven, ... the minimum kit is the plan AND the complete tail. Full fiberglass kit (all composite parts to finish it as the prototype) and plans are available, as well as full materials kit and complete kit ( more info at www.aviomania.com).

Plans are very detailed (sample plan in the website), full scale ( except the long pieces that are 1:10 with the dimensions stated) plus a template sheet (you can cut out the parts and stick them on aluminum so you can cut it.

we are building one and making video manuals that can be viewed in our web page (soon we will start uploading)

I am very strict with the plans, for example... hung angle will be obtained by moving weighs ( battery, pilot seat, exhaust) and not by moving the rotor head position as everybody else is doing..... if somebody decides to put a heavier engine and needs to move the rotor head 5" to the rear for the hung angle to be correct that means that he is moving the center of pressure 5" forward in relation to the CG....= less stability.

on the other hand if you just move the battery from behind the seat to the nose (there is a designated place to do so) you will have the correct hung angle and still maintain the stability of the prototype.

Option for triangulated undercarriage with suspension also available.

It is not difficult to built my gyro... it will take more time than a bensen type but the end result worth that extra time.

we are also working on 4130 welded main frame that will be very easy to assemble and still be within the 51% rule. Also working on a ultralight version...

Thanks for the comments..... have to go ..tooooo.... busy...

[WHY]

WAY TO GO NICOLAS !!!!!!!!!!!!!!! VERY smart move on the kit arrangement.

Hope to see them in USA very soon !

Tony

[jehicks87]

ken wallis's design... Are there plans available for that?

[WHY]

jehicks87

Not sure but think most of his design used round tubing ??????? Using the 2x2 square tubing for the basic keel, mast, frame construction will be much easier then add brackets for the gear and tail

Tony

[WHY]

If I wasn't already building a tractor I would for sure be building a raked keel design pusher using a HKS for the engine. Not a real designer, but as a "armchair" observer it looks like the basic set up for a raked keel is to set mast at 90 degrees to the keel then raise the nose of the keel 10 degrees for the proper angle on the mast, add another piece from the mast to the nose to make sort of a triangle with the nose having a short piece about 6 inches to a foot long to make a great mount for the nose gear and the back end of the triangle piece attached to the mast up about a foot to foot and a half.

Then depending how high you want the frame to be either leave the keel straight or cut it a little ways behind the prop and plate on another section that is level for the stab and rudder. About the only other part that will need some maath work is the attachment of the main gear especially if you want sprung gear.

I'll bet thery is plenty of help out there if you want to try to build one. The raked keel is a natural for CLT.



Tony

[Passin' Thru]

ken wallis's design... Are there plans available for that?

No! Sometime back there were some "boot-leg" plans that claimed to be a Wallis design, but as I understand it, Wallis filed suit to "cease and desist".

An interesting bit of trivia; Wallis built a Gyro Glider based on plans he purchased from Bensen in the late 50's. This was the Bensen B-7.
While serving the RAF in an exchange program with SAC, he aquired a couple of Mac drone engines and had them shipped back to England. Of course, he modified them to his own specifications and fitted one to the B-7 gyro glider. This was his experimental "learning tool" which was re-designed to become the WA-116 which we all saw in the Bond movie. Since then he has built 19 variations.

[jehicks87]

so his design is lost forever? Thats a shame.

[Passin' Thru]

so his design is lost forever? Thats a shame.

Not really. There are enough photos of most of the details floating around one could "pick it off" and build one, but I wouldn't call it a Wallis! :tape:
.

[dingbat]

maybe another one for luck!

Pics are off an origanal drawing sorry about the clarity!












G.
LAA.PRA.BRA..............:plane:

[SnoBird]

No! Sometime back there were some "boot-leg" plans that claimed to be a Wallis design, but as I understand it, Wallis filed suit to "cease and desist". An interesting bit of trivia; Wallis built a Gyro Glider based on plans he purchased from Bensen in the late 50's. This was the Bensen B-7. While serving the RAF in an exchange program with SAC, he aquired a couple of Mac drone engines and had them shipped back to England. Of course, he modified them to his own specifications and fitted one to the B-7 gyro glider. This was his experimental "learning tool" which was re-designed to become the WA-116 which we all saw in the Bond movie. Since then he has built 19 variations.

Interesting, thanks for sharing that info. But does Wallis have a copyright on his design? Does he have patented innovations on it? If so, surely they've run out by now? As to the remaining design, I don't see how it differs enough from other gyros to legally prohibit others from making and marketing it.

And where did you hear that Wallis got his start using Bensen machines as a template? I've always wondered who came first, it would be great to learn more about this subject if you have any further facts. Thanks...

[Passin' Thru]

Interesting, thanks for sharing that info. But does Wallis have a copyright on his design? Does he have patented innovations on it? If so, surely they've run out by now? As to the remaining design, I don't see how it differs enough from other gyros to legally prohibit others from making and marketing it.

Start at the bottom;
I don't see how it differs enough from other gyros to legally prohibit others from making and marketing it.
I'm not an attorney, so I couldn't say absolutely, but as I understand it, the "boot-leg" plans were using his (Wallis') name for promotion. It's possible they could have gotten away with it if they had just called it the "Bumerklotz 29", or some such?

Does he have patented innovations on it?

Yes! One of them is the Offset Gimbal Head! And therein lies another tail! Wallis was in the military service when he was patented it and therefore the patent became property of the Crown. When Bensen introduced his version in 1964, the Crown elected not to contest Bensen's claims. There's more to that story, but I'll leave it for now and see if I can find the old article. You may find it interesting.

[Jazzenjohn]

<If I wasn't already building a tractor I would for sure be building a raked keel design pusher using a HKS for the engine>

Hey Tony... Don't go stealing my fire now... I've been doodling stuff since pile o' parts was finished figuring out how I can make it both lighter and smaller.

[C. Beaty]

Yes! One of them is the Offset Gimbal Head! And therein lies another tail! Wallis was in the military service when he was patented it and therefore the patent became property of the Crown. When Bensen introduced his version in 1964, the Crown elected not to contest Bensen's claims. There's more to that story, but I'll leave it for now and see if I can find the old article. You may find it interesting.Cierva first patented the offset gimbal rotorhead in the early 1930s.

A patent is said to be presumptive until it’s been tested in court.

[SnoBird]

I'm not an attorney, so I couldn't say absolutely, but as I understand it, the "boot-leg" plans were using his (Wallis') name for promotion. It's possible they could have gotten away with it if they had just called it the "Bumerklotz 29", or some such?
Well I can certainly understand if the sellers of the boot-leg plans used Wallis' name and/or likeness to market their product. That'd be a non-starter and I'm sure they would be legally culpable for doing so. But if a gyro manufacturer made and sold a nearly identical machine, I just don't see how a legitimate legal threat could be waged against them. All of the singular features on the Wallis machine have been on many machines of the past and present, and some machines have all of the features incorporated. And, if what you're saying is true, the basic Bensen-type machine was around before Wallis came into the picture anyway. And before Bensen there was Hafner's Rotachute, the German FA-330, and before them Cierva - the grandaddy of them all. I just don't see how Wallis or anyone without an active patent could step up and decry copyright violation or patent infringement, especially considering how long this technology has been around (to my knowledge patents usually have a lifespan of 20 years).

All of that aside, the vast majority of those who build gyros today use larger props than the old direct drive Mac system. If someone would try to market a Wallis clone machine, they'd have to pretty radically change its design to accommodate the larger prop. And if they did that it essentially wouldn't be a Wallis type machine anymore, it'd be a run of the mill modern gyro (with an H-stab at that). Much of the benefit of the Wallis machine, that being its small size (hence light weight + manueverability) and inherent stability, is because of the direct drive/small prop system. Take that away and you strongly venture away from the original concept. Now, what I think would be interesting is if someone were to take a modern engine and put a reduction drive on it, but still retain the use of a smaller prop spinning at a speed comparable to that of a mac (or possibly a ducted fan system) and incorporate that into a Wallis clone machine. You'd take a hit in propulsive efficiency, but you'd save weight and probably at least some aerodynamic drag. The savings in power from those two benefits might be enough to offset the loss in propulsive efficiency to the extent it would be worth it. Maybe... ;)

[jehicks87]

Not really. There are enough photos of most of the details floating around one could "pick it off" and build one, but I wouldn't call it a Wallis! :tape:
.

I was more thinking along the lines of Beginners looking for a proven, storied design to build. I doubt any "beginners" are going to want to tackle piecing together something they know very little to nothing about from pictures found on the internet.

Oh well, there are plenty of other good designs out there...

[dingbat]

hi,
well this is an interesting post!
If... and only if.. you could get one of the gyrocopters form ken wallis as a gift..you will be in for some pain!:(
The reason for this is because in england if the gyrocopter has no permitt it would have to go under (section T )which means there is an endless list that has to be updated before a permitt to fly would be granted!...and before the permitt the gyro has to get a pass for even a test flight by the CAA before a permitt is issued! and all faults have to be corrected!
I know i am on this road at the moment!
You would probbly be better of starting on a totaly new project..than stripping a totaly flyable one that has been flying..and have to start stripping it down compleatly this is totally... soul destroying these are the UK rules sad as they are!

:focus:




G.
LAA.PRA.BRA.................:plane: