Morgan restoration

[3rd harmonic]

8 hours ago, graham brown said:

The plans have the tail wheel version but the steel frame needs turning around which means a fair bit more pulling apart.

 

Hey Graham, do your plans actually specify a main gear location for a T/W configuration? The original plans I have don't have any such indication.

Turning the steel frame section around (which I'd never thought of) would mean the main L/G is only about 70mm in front of the wing spar, which would be abit too far back by my estimation. The T/W A/C pictured above has the gear around 200mm in front of the wing spar or just behind the wing leading edge. This is actually a great unknown I have to admit. I'm going to have a 180mm range of adjustment in 9x 20mm steps for the main L/G position which should hopefully allow something workable. But actual info would be greatly appreciated.

Ab

[graham brown]

I just had a look at the plans and they do not have the location of main landing gear in relation to the airframe for a tail dragged. The only direction is to turn the frame around. This would set the distance of the mains in relation to the spar. Gary use to mark the longerons where the frame had to be bolted to the longerons. Mine was for a tricycle. It would have been different for the tail dragged. 

[3rd harmonic]

Thanks for looking, that is interesting info...

The steel frame section has to be close to the widest point on the fuselage by design in the way it supports the longerons as they are curved under tension, but that could be abit different in relation to the nose or firewall.

The inside of the previously pictured A/C shows the L/G bolts forward of the tube that forms a triangular shaped gusset.

This is where I'm up to with the L/G attachment bracket - the white template is 2x holes on a 120mm spacing that will form the new L/G mounting clamp which is parallel with the A/C centre line. There is no floor or skin at the moment!

Edited November 12, 2023 by 3rd harmonic
accuracy

[graham brown]

That looks like you will have plenty of adjustment there. 
Does your Sierra have wing tanks or just the front tank?

The fuel load is appreciable to the all up weight and wing tanks would be the way to go. I wish I had done that.

[facthunter]

Do you mean applicable?  Wing fuel is easier on the structure.   Nev

[graham brown]

I meant a significant proportion. This weight in the wing doesn’t move the position of the CG as much as it does in the forward tank position. As you say easier on the structure too.

[3rd harmonic]

No wing tanks, just the front tank behind the instrument panel.

I looked at the A3 plans again and while they do show details for attaching the T/W, no detail as to the position of the mains.

I have opted just to add steel to the structure to make it happen like the T/W A/C pictured.

 

[Blueadventures]

Is Gary contactable in NZ?

[IBob]

Here's another one (in NZ):

https://www.trademe.co.nz/a/motors/aircraft/aircraft/listing/4417353949?bof=cc5AdFfN

[Blueadventures]

1 hour ago, IBob said:

Here's another one (in NZ):

https://www.trademe.co.nz/a/motors/aircraft/aircraft/listing/4417353949?bof=cc5AdFfN

Looks a good bargain for someone over your way.

[kgwilson]

Messy panel & a few odd construction bits but a massive bargain. The engine is worth more that the asking price.

[graham brown]

Yes the nose leg problems that pilots have had has scared off the punters so the prices are way too low. Once the nose leg is beefed up and you keep the weight off the nose wheel through better CG management and pilot technique they are a delightful aeroplane to fly. A very fast cross country aircraft too. 

[graham brown]

Just to cheer up the Morgan owners and talk up the price here is a picture of mine/me at Cessnock 2018 when I took it to the airshow to Ray’s exhibition. The Sadler Vampire Ray had there got more attention though. Haha

Hope it inspires you Andrew.

https://www.airhistory.net/photo/524759/19-8651

 

[facthunter]

IF the mainwheels are back too far it requires a lot of elevator downforce  to raise the nose and that adds to the weight on the mains and doesn't work as you slow up. It also affects the way the plane lifts off.   Nev

[graham brown]

1 minute ago, facthunter said:

IF the mainwheels are back too far it requires a lot of elevator downforce  to raise the nose and that adds to the weight on the mains and doesn't work as you slow up. It also affects the way the plane lifts off.   Nev

That’s the issue and symptoms right there

[IBob]

28 minutes ago, facthunter said:

IF the mainwheels are back too far it requires a lot of elevator downforce  to raise the nose and that adds to the weight on the mains and doesn't work as you slow up. It also affects the way the plane lifts off.   Nev

Yep, same problem if the C of G is too far forward: once the main wheels are down, the elevator won't keep the nose up as the aircraft slows.
I have this with my Savannah, which I often fly solo and quite light: I recently added 10kG of (removable) ballast in the baggage area and it is now a completely different aircraft to land.
The main difference I notice in liftoff is more rudder to hold her straight during initial acceleration, presumably as the nosewheel is effectively lighter.

Edited November 12, 2023 by IBob

[graham brown]

6 minutes ago, IBob said:

Yep, same problem if the C of G is too far forward: once the main wheels are down, the elevator won't keep the nose up as the aircraft slows.
I have this with my Savannah, which I often fly solo and quite light: I recently added 10kG of (removable) ballast in the baggage area and it is now a completely different aircraft to land.

Yep CG management helps a lot. In the gliders we have tail tanks to manage this and the charts are critical. The airliners manage their CG too. GA pilots have been spoilt by the Cessna etc it is not the norm and requires careful adjustments for best results.

[3rd harmonic]

1 hour ago, graham brown said:

Just to cheer up the Morgan owners and talk up the price here is a picture of mine/me at Cessnock 2018 when I took it to the airshow to Ray’s exhibition. The Sadler Vampire Ray had there got more attention though. Haha

Hope it inspires you Andrew.

https://www.airhistory.net/photo/524759/19-8651

 

VERY NICE  - how many more kts does the chequered flag rudder give you? Morgan owners can also boast that the all flying elevator avoids the pitch down moment in trans sonic flight approaching the sound barrier.

[kgwilson]

The full flying elevator (stabilator) needs very little movement to effect pitch control & some people find this a bit disconcerting. I flew an Archer 2 for 20 years or so so I prefer this to fixed horizontal stabiliser & elevators. The Archer had a pitch activated trim as well as an electric activator. Half the time the electrics didn't work though so the wheel had to be spun manually.

 

My first bent nose leg had nothing to do with the position of the mains, it was the tendency to float in ground effect with a little too much speed on (plus the engine idle set a bit fast) & the weak nose wheel leg hitting the mud. My new one would just plough through it now. The second was a brain fart when making the leg 50mm loo long. The attitude for landing is quite subtle so the nose wheel is only about 50-60mm off the ground when the mains touch down.

 

After I reset the idle screw I often stopped the engine when pulling the throttle and did quite a few dead stick landings & restarted on roll out.

 

I have  2 x 35 litre wing tanks as well as the 100 litre fuselage tank. I have never landed with 100 litres in the fuse tank but have with 80 and had no issues.

[graham brown]

I wish I had put the wing tanks in. With the front tank full it’s hard to get the nose up initially and as the speed builds up you have to come a long way forward on the stick in order not to get too slow. With 80 litres or less it’s not an issue. I’ll report if there is any change when I get mine going again. My mod to the UC makes it very easy to move it back again anyhow.

[3rd harmonic]

Good discussion about CofG in relation to weight and balance, the importance can't be overstated...

Having done some research and reading to inform my thinking - For a tail wheel A/C a tangent from the contact point of the main L/G should make an relatively acute angle to the nominal CofG as per this diagram - other diagrams specify slight different range of angles 12-18 degrees ect

 

Unfortunately in all the paper records i have from the original build of my machine i can't see any evidence of the aircraft weight and balance having ever been measured/documented and that really isn't wonderful...

As i am led to believe from reading though the RAaus info, measuring the A/C weight and calculating the balance is NOT an optional part of the process of getting a provisional airworthiness certificate granted for a new experimental build.

Did you guys KG and GB do that as part of getting your machines inspected before test flying?

Do you guys happen to know where the Cof G actually is on your A/C for nominal pilot weight say 80kg + full fuel in the front tank and/or minimum fuel?

[facthunter]

The further the wheels are forward of the C of G, the more directionally unstable it will be but you can apply more braking force. Your Plane MUST have the C of G in the Designer's range and not require fuel to keep it there.  Every plane should have it's Basic wt and Index determined and recorded for the flight.  It's the operator's job to load it correctly to keep it in the range allowed and have a method of doing it . Nev

[graham brown]

2 hours ago, 3rd harmonic said:

Good discussion about CofG in relation to weight and balance, the importance can't be overstated...

Having done some research and reading to inform my thinking - For a tail wheel A/C a tangent from the contact point of the main L/G should make an relatively acute angle to the nominal CofG as per this diagram - other diagrams specify slight different range of angles 12-18 degrees ect

 

Unfortunately in all the paper records i have from the original build of my machine i can't see any evidence of the aircraft weight and balance having ever been measured/documented and that really isn't wonderful...

As i am led to believe from reading though the RAaus info, measuring the A/C weight and calculating the balance is NOT an optional part of the process of getting a provisional airworthiness certificate granted for a new experimental build.

Did you guys KG and GB do that as part of getting your machines inspected before test flying?

Do you guys happen to know where the Cof G actually is on your A/C for nominal pilot weight say 80kg + full fuel in the front tank and/or minimum fuel?

Yep sure did do the weight and balance it’s mandatory.

Gary specified the the range of CG to be 8inch to 14inch from the leading edge. Attached is my XL spread sheet and graphs.

[kgwilson]

W&B is a requirement for registration of any aircraft RA or GA & also in NZ. Mine was done with a set of interconnected aircraft load cells. You can use 3 x bathroom scales that you have calibrated, at least you could when I built mine. I used the spinner tip as the datum & CoG limits are between 15% & 33% of the wing root aft of the leading edge. The empty weight of mine was 335kg or 22kg heavier that Garrys standard weight & included my mods including electric flaps, wing tanks, Matco disc brakes,  etc.

Edited November 14, 2023 by kgwilson

[3rd harmonic]

Thanks guys that really is SUPER helpful!

Every aircraft is always going to be abit different, as has been noted, but that info will at least give me abit of a guide to work off in doing some calculation to see if the new main L/G position will fall within an acceptable window.

I have been keeping a tally of the weight of steelwork added vs components removed and at this stage i'm in front by about 2kg.

Not withstanding the reduction in drag by not having a nose wheel.

 

5 hours ago, facthunter said:

The further the wheels are forward of the C of G, the more directionally unstable it will be but you can apply more braking force. Your Plane MUST have the C of G in the Designer's range and not require fuel to keep it there.  Every plane should have it's Basic wt and Index determined and recorded for the flight.  It's the operator's job to load it correctly to keep it in the range allowed and have a method of doing it . Nev

Yes, there is always a compromise with any design choice and accord to this article (https://www.kitplanes.com/design-process-landing-gear-part-6/) the main L/G position on the C140 was perhaps less than optimal??!