This is a photo of the last RAF that i have changed the thrust line on.
The engine and redrive have been lowered 6 inches and i put the tail back a further 8 inches than a standard RAF .
This is a photo of the last RAF that i have changed the thrust line on.
The engine and redrive have been lowered 6 inches and i put the tail back a further 8 inches than a standard RAF .
Tim and Tim we had a test program flown by a qualified test pilot with thousands of hours in gyros.With the lack of a gyro test flight program at hand we used a fixed wing one the gyro past the test with ease, when the setup was done the machine was able to be flown on a one hour cross country flight with only using a little rudder and throttle only using the stick to land.
Harry the mast was there when the machine arrived, why any one would want to fly with a 5 to7 degree keel angle and try to push that windscreen through the air at that angle'' i dont know''.
The gyro now flies with a level keel.
Paul the tail is at the same level and 8 inches back the clearance is good but i would be hesitent to go any further back or up,we also moved the axel back 5 inches.
First, my apologies in even asking this question since I'm a newbie still wrapping my head around flight issues.
In the original post you mentioned lowering both the prop AND the engine by 6". Would it have been advantageous to lower the prop somehow without lowering the engine, since the engine is a heavy mass that affects VCG?
There is much I don't know about aircraft design, which is why I'm asking. (And by the way I love your S-Keel ). It just seemed that lowering the engine too might hinder the efforts where a high engine/low prop might be more advantageous, and useful with your new keel clearance design.
Again, I'm only a student of weight & balance issues with a lot yet to learn.
Mr Jackson
You are right in theory how ever bringing the two main heavy parts pilot ,fuel closer to engine redrive is a better balance than a standard raf.
the best would be to lift the engine and put a gearbox on and new prop opposite rotation and tail with opposite offset but i am bit cheap and easy,the cost with what we do is only just a little over $2000 US including my labour
They could use the Sparrowhawk Reduction unit and leave the engine where it was. Better than what they are doing, but of course more expensive - unless they could sell the old RAf redrive to offset some of the cost.
When I did my conversion, I estimated it could be done for 2-300 dollars and a weekend. The engine will encounter no resistence items by dropping it 6 inches on a old machine. Cut the keel behind the radiator and add the newly constructed keel with all the angles. The keel i made attatches at the axel point and is boxed to the old keel with 6061 aluminum plate and lots of SS rivets and 1/4 inch bolts for stregnth.Drop the radiator down to the new keel. Other issues are you will have to redo your rudder cables or add legnth. Don Parham did my cg and clt math. He says the CG hardly changed at all and the clt is at 4.12 inches above CLT.That could move based on the weight of pilot or pilots and fuel.All in all, if you take a stick and hold it at the bottom and push at the top you have a lot of leverage and that has been the issue with any HTL machine. Move your top hand down the stick and you have a lot less leverage. I had one person tell me I went to a lot of work for nothing. After talking to 1 person who made this conversion plus what has been posted on other conversions like this I believe that this is the way to go for people that have reservations on the high thrust line of a RAF. You maintain the appearance with out the high weight issues that have appeared with the Sparrow hawk and tipovers.You keep your foulding mast and actually decrease the chance of a rollover by keeping the weight low.. All that for a couple hundred bucks and a weekend.i will report the flight tests hopefully this weekend.This is your unbiassed( and Republican conservative) reporter signing off.
A gyro is not a bloody go cart if you taxi at the appropriate speed there is not a "Rollover Issue". Take turns slowly and only accelerate in a staight line, no roll over issues. I am tired of hearing these same excuses for not getting the thrustline in line with the CG. The other is " I don't want to have to climb up to get into my gyro". They would be the first to climb up to get into a big biplane if someone offered them a ride.
How about a side load in a hairy crosswind. I'll take the The lower CG. As for taxi, you are right!!!
Mike, sorry you didn't like my post. as Gremminger says, "there's more to it than CLT." (and he is right)
Also I don't want to climb up into my gyro.
Larry,
Greg's opinion about clt has changed since he has put all his eggs in the italian basket. Before his affiliation with Magni he was one of the biggest propants for clt and tall tail with a centered horizonatal stabilizer. A large vertical stabilzer should be able to handle any crosswind. Never heard of one of these long legged beasts my dad builds ever having a problem with a crosswind.That little bitty tail on the RAF is a is too small. I am suprised we don't hear of more Raf's wanting to swap ends. "Also I don't want to climb up into my gyro". I don't suppose you better ever own a pickup truck since you don't like to climb.Then on the other hand you can take to the boys at West Coast Customs and have them lower it so it feels like you are getting into your RAF. LOL.
Joe we just used plates and rivets as per RAF manual.
Birdy i stuffed up the photos for the pitcher methode the proof was in the flying for me, the maths people say about 7 inch
Mike. I own a Expedition and I do have to climb up into it. It has a step to help me do it. But thinking about it, I got used to doin it. I guess I could get used to the Sparrowhawk and stepping up into it. My friend Andy is building one so I better practice up.
As for the swap end thing, I never experienced the RAF wanting to swap ends but I believe all things are possible.