Morgan Sierra safety

bexrbetter

Well-Known Member
#61
what do others (including builders) think of pop rivets going into FRP ribs? Is the fibreglass strong enough to hold a rivet over time...
Yes, no problem. I have rebuilt a number of '60's and 70's Ossa, Montesa, Bultaco and the odd 1960's Rickman that have a number of riveted fiberglass parts in a vibrating, stressful situation and none were an issue after 30 to 40 years. Done some fiberglass kitcar stuff as well using rivets for various things.

Also, the stabilator appears to have all the FRP ribs epoxied to a single metal torque tube (is that the right term?). Again, it seems to me in the long term that epoxy might lose adhesion to the metal due to uneven expansion/contraction.
Correct and probably not ideal, not because of contraction etc, but simply because fiberglass doesn't bond to metal permanently and one day it will separate, that's a given, the question is "when", not "if". That could be 100 years but I still don't like those odds.

There's 6 ribs per side, after glassing as per instruction, pop a rivet in the second and third from the outside on the vertical face facing the rear (where the tube is in compression), and 4 rivets equally around the circumference on the outside one (number 6). Do not rivet the inside 3. That will be enough.
 

kgwilson

Well-Known Member
#62
There are cable ties and cable ties. Good quality nylon cable ties will outlast the rubberised fuel line that they are constricting and so long as they are not exposed to ultraviolet radiation, as stated by others they are better than hose clips. ATSB were looking for anything they could find to assign blame. The same as whinging about an electrical cable being cable tied to a fuel line. As Garry pointed out there are electrical cables routed inside fuel tanks in many aircraft.

The fibreglass ribs have a CSM base with a roving cap around the rivet face circumference. The rivets are very solid in this substrate. I suspect that Bex's use on motorbikes had perhaps thicker glass but less extensive reinforcement.

I have no concern with the glass to alloy tube assembly of the stabilator. Glass does not stick well to a smooth alloy surface but rough it sufficiently and it won't separate.
 

Garry Morgan

Morgan range of aircraft
#63
The fiberglass rib will still be in one piece long after a metal rib has cracked and fallen out over time. only the Cheetah rear rib that has more load on it we use metal washers.
The tail spar roughen up to attach the glass rib, the glass is always shrinking to the tube and making the bond tighter over time. its not going anywhere, and vibration is not going to have any effect over time. its the best of all worlds.
 

turboplanner

Well-Known Member
#64
The tail spar roughen up to attach the glass rib, the glass is always shrinking to the tube and making the bond tighter over time. its not going anywhere, and vibration is not going to have any effect over time. its the best of all worlds.
Yes it's a good application of FRP which shrinks around an object. Have used it for large steel outlet couplings on fuel tankers and fire crash tenders.
 

bexrbetter

Well-Known Member
#66
The tail spar roughen up to attach the glass rib, the glass is always shrinking to the tube and making the bond tighter over time. its not going anywhere, and vibration is not going to have any effect over time. its the best of all worlds.
Sure Fiberglass is asymptotic, but it's main shrinkage takes place over the first week or 2 and the shrinkage is not greater than it's expandable range due to heat. Not my opinion, scientific fact.

Fiberglass does not permanently bond to metal, roughened or not, and again, not my opinion, that's factual science. The joint will eventually fail, go ask 3M, Selleys, Cyberbond or someone similar.

Besides just knowing how poorly metal and fiberglass bonds from many years of playing with the stuff and that's it's veritable lore (for a change), I did a whole series of dedicated coupon and other testing last year including fiberglass and a range of expensive epoxys. Here is some of those tests, some Morgan builders might recognise the offcuts in the video ....



epoxy.jpg

All tests failed to be considered as a standalone joint, fiberglass easily one of the weakest. Surprisingly, common hardware store "Liquid Nails" type was consistently one of the best and is actually the video above.

Anyway, not here for a fight, I was asked the question and I answered. If you choose to fly with the standard setup, that's your prerogative, I won't and for the addition of 5 minutes work and a couple of rivets I don't see why anyone wouldn't support that.
 

facthunter

First Class Member
First Class Member
#67
In flying IF there's any doubt, try and make it NO doubt. Testing assemblies as a sample relies on the assumption the variation on quality is small. The Fokker F27 was redux bonded.( Thermosetting I believe) The Fairchild version was riveted . Later....More fatigue without the glue. but that's another aspect..Nev
 

Downunder

Well-Known Member
#72
I offer you a categorical assurance of "No".

I simply needed an easily modifiable plane to test some ideas and conduct some engine experiments with and I didn't have time to scratch build my own - and as always, I chose to spend my money in Oz.
I'm definitely not saying there is anything wrong with doing it. Might even be a good thing.
I'm not a China basher....... It's simply the manufacturer to the world.....
 

bexrbetter

Well-Known Member
#73
I'm definitely not saying there is anything wrong with doing it. Might even be a good thing.
I'm not a China basher....... It's simply the manufacturer to the world.....
No problem, I wasn't referencing it towards China nor did I take your comments as me possibly doing it that way because I'm in China, I just don't believe in the theft of other's hard earn't IPR (intellectual property rights or patents, legally registered or not) regardless of where I am at.

I'm definitely not saying there is anything wrong with doing it. Might even be a good thing.
I had the idea some years ago and I contacted every Australian aircraft company I could find including digging up dead ones. Spoke or visited them all bar one. With the exception of none, all have some serious delusions of how awesome they are pertaining to their worth and or product, the levels vary of course from genuine pride in themselves, understandable, to the one guy who thinks his business is worth triple the total value of his entire retail sales for the last 20 years.

So yeah, nah, I'll pass thanks.
 

turboplanner

Well-Known Member
#74
Fiberglass does not permanently bond to metal, roughened or not, and again, not my opinion, that's factual science. The joint will eventually fail, go ask 3M, Selleys, Cyberbond or someone similar.
That is correct, but we were talking about FRP being laid in such a way that when it shrinks it locks on to mutilated steep and the mutilations - grooves and protrusions provide a mechanical lock.
 

bexrbetter

Well-Known Member
#75
That is correct, but we were talking about FRP being laid in such a way that when it shrinks it locks on to mutilated steep and the mutilations - grooves and protrusions provide a mechanical lock.
Oh I understand exactly what's being proffered. After the bond has broken, over time the back and forwards movement will grind it smooth and eventually slip around.

Sure, that may be 100 years and millions of cycles ..... but maybe not. Who knows, you guys are only guessing and you have no empirical evidence available, that's the problem. You may have sealed up some static pipes, but this joint has constant cyclic shear stress applied along with constant expansion/contraction at different material rates trying to tear it apart - even when it's just sitting.

I've stated the plane is very safe and crashworthy so I'm obviously in support of the design overall and I have promoted the Morgan to individuals ho ask and in the HBA forum. I'm not here to cause drama and panic, but this bit is simply not up to my standard and it's technically not a good idea, as well as the fuel tank construction being too thin considering it's in the cockpit. A couple of simple rivets fixes this issue, lay up the tank thicker or replace it (as Sloper did) fixes the other. Minor, but important fixes.

It's not law to build to the original specs, that's only a guide, once the kit is in your possession it's up to you.
 

turboplanner

Well-Known Member
#76
Oh I understand exactly what's being proffered. After the bond has broken, over time the back and forwards movement will grind it smooth and eventually slip around.

Sure, that may be 100 years and millions of cycles ..... but maybe not. Who knows, you guys are only guessing and you have no empirical evidence available, that's the problem. You may have sealed up some static pipes, but this joint has constant cyclic shear stress applied along with constant expansion/contraction at different material rates trying to tear it apart - even when it's just sitting.
Just leaving aside the Morgan design, and talking about the principle of using FRP and steel or aluminium in combination.
There is no bond to break; you'd have as much success bonding FRP to aluminium with polyester resin as getting a pelican to breathe under water.

There has to be a mechanical entrapment

As far as "guessing" and "no empirical evidence available", I can tell you about the design of one piece moulded, frame-free sandwich construction refrigerate vans where Australia leads the world, because I was directly involved in it.

When you see one of these on the road, have a look at the refrigeration unit, it's bolted to two pieces of MS flat enclosed in the FRP.

In the semi trailer refrigerated vans, the lights, heavy duty door hinges and cam locks are all bolted to small, localised steel plates, as are the skid plate and the tri axle
suspension. The one piece FRP box is structural, has no chassis.

About 14.5 tonnes static load is going through the skid plate and about 17 tonnes through the tri axle suspension.

As for empirical evidence, the first of these went on the road about 50 years ago; most are still in service.



S3148A.jpg
 
#77
Referring to Australian designs being built under licence in China, has anyone heard how Brumby is getting on doing that? They were going to manufacture their two-seater in China and concentrate on their 4-seater at Cowra. Has anyone go any info about that?

OME
 

Geoff13

Well-Known Member
#78
Just leaving aside the Morgan design, and talking about the principle of using FRP and steel or aluminium in combination.
There is no bond to break; you'd have as much success bonding FRP to aluminium with polyester resin as getting a pelican to breathe under water.

There has to be a mechanical entrapment

As far as "guessing" and "no empirical evidence available", I can tell you about the design of one piece moulded, frame-free sandwich construction refrigerate vans where Australia leads the world, because I was directly involved in it.

When you see one of these on the road, have a look at the refrigeration unit, it's bolted to two pieces of MS flat enclosed in the FRP.

In the semi trailer refrigerated vans, the lights, heavy duty door hinges and cam locks are all bolted to small, localised steel plates, as are the skid plate and the tri axle
suspension. The one piece FRP box is structural, has no chassis.

About 14.5 tonnes static load is going through the skid plate and about 17 tonnes through the tri axle suspension.

As for empirical evidence, the first of these went on the road about 50 years ago; most are still in service.



View attachment 35748
FTE I think it was pioneered that setup, although I may be wrong. I can't recall seeing to many still around over 15-20 years old though.
 

turboplanner

Well-Known Member
#79
FTE I think it was pioneered that setup, although I may be wrong. I can't recall seeing to many still around over 15-20 years old though.
Reinforced Plastics Pty Ltd built the first and converted the market from the much less efficient steel/aluminium framed vans, and were joined by Athol Hedges Pty Ltd, a Brisbane based builder.
FTE was started some years later by the RP General Manager, and one of the draftsmen, still make them, and do a magnificent job.
Some of the 1965 vans have been on 7 or 8 cab/chassis, and usually the only maintenance required is a repaint. A few have been lost in major accidents, and several more failed after minor skin damage which was not repaired, allowing water in to the sandwich panel destroying it. I keep a watch around the eastern states, the old ones - RP and Athold Hedges can be identified by their front clearance light recesses, and I'd suggest that about 80% of all production is still in operation.
 

Geoff13

Well-Known Member
#80
Reinforced Plastics Pty Ltd built the first and converted the market from the much less efficient steel/aluminium framed vans, and were joined by Athol Hedges Pty Ltd, a Brisbane based builder.
FTE was started some years later by the RP General Manager, and one of the draftsmen, still make them, and do a magnificent job.
Some of the 1965 vans have been on 7 or 8 cab/chassis, and usually the only maintenance required is a repaint. A few have been lost in major accidents, and several more failed after minor skin damage which was not repaired, allowing water in to the sandwich panel destroying it. I keep a watch around the eastern states, the old ones - RP and Athold Hedges can be identified by their front clearance light recesses, and I'd suggest that about 80% of all production is still in operation.
Thank you. Yes the FTE's also stand out for a similar reason with the lights. Yes I am aware of many bodies that are in use with plenty of age on them, I was actually referring to the full trailer setups that I don't see to often any more. I know that they are far better design to tow both empty and loaded than any of the earlier full chassis designs. The FTE's in particular (I only mention them because I had plenty of practice with them.) had far better cooling ability than any other van I towed as well. So much so that and FTE van could carry a load of icecream from Perth to Brisbane and use less than half the fuel in the Fridge motor of an equivalent maxicube trailer.
 
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