At 9k, their gross margin will be in excess of 95%. Yes, $8.5k gross profit. That is how the “TC owner” business model works. They buy the material for ~nothing, and use their TC + 145 + in-house-DER / Easa21 cert to produce certified parts. Socata do this all day long; even bought-in parts often come from obscure French homebuilder-market vendors (one sometimes finds them in a far corner at EDNY). Of course you don’t make 95% gross on a whole plane but that’s because (a) you buy in most parts for $lots and (b) you pay for months of labour.
The challenge is to sell enough to make it worth the documentation / tooling effort. But the fleet size is huge; few GA fleets are bigger.
Apparently Beechcraft is possibly going to produce replacement ruddervators as an OEM part, at the possibly ‘reasonable’ $9,000 a piece. You need two by the way.
I doubt they can make money on this, so it may be an act of ensuring the brand integrity is protected. In all its variants there are over 10,000 Bonanzas/Debonairs still out there.
Surely, labour cost dwarfs the material cost, of e.g. 0.8mm rolled titanium sheet. Re-skinning an elevator is a seriously skilled job which needs to be done very accurately otherwise you get trim issues which will never be solved – see e.g. this. The average Part M workshop has little chance of doing it properly, IMHO. There was a long report here somewhere on somebody re-skinning a TB20 wing and it took him for ever, and he really knew what he was doing.
Peter wrote:
Titanium is OTOH a really amazing material. Perhaps one could use it for the skin?
If money is no object, probably!
I opine that the choice of magnesium for some Beechcraft control surfaces was probably influenced by designers who had used it in military aircraft designs they’d been involved with previously. It made the plane more efficient, at a monetary expense. At the time of manufacture of the plane, that cost difference was not that great, and the extra processes for corrosion protection were easily accomplished. Decades later, in the field, maintenance is not so easy. And remember that no GA airplane manufacturer intended for their planes to be flying this many years. So they’re not rushing to produce low cost replacement parts, it’s an “it costs what it costs” situation.
The change of product by STC is certainly possible, and I have approved different skins on Cessnas. But the balancing of flight controls, and subsequent testing for approval is a daunting task. In the next couple of weeks I have some flutter testing to do during approval flight testing of a Grand Caravan with a wing mod. The new expectations for active flutter testing imposed by the regulator are really burdensome. In this regulatory world of caution, would make it a big job to approve different flight control skins. It can be done, it’s just costly. One by one, airplane owners cannot bear the cost. Legacy airplane owners need to organize themselves into type clubs, and have the club bear the approval cost on behalf of all of their members for the desired mod.
Exotic materials are just that, exotic, and usually not appropriate for GA planes. Keep it as simple and common as possible to keep maintenance costs down in the future. Cessna and Piper lead the market in building compromise planes, and they are, but en mass, they’re still flying, where other more exotic types were not economical to maintain. Recent ADs on both Cessnas and Pipers are showing the concerns of aging airplane structures – but those planes served well past their intended lives to begin with….
Silvaire wrote:
A lot of things could be done if the STC process was amenable.
Agree entirely and frankly this again all boils down to liability law and the manufacturers unwillingness to move. Bit like TBO on engine/motor hours.
A solution will be found and the problem will vanish, but there will be a cost where the customer will pick up the tab.
The TB 30 uses fabric covered controls, to save weight and thereby if I understand correctly boost the flutter speed. Same concept but older and arguably better technology.
If obtaining magnesium replacement skins is truly problematic, carbon fiber replacement skins are lighter than magnesium and I suppose that might work in a ‘black magnesium’ direct replacement scheme. The skins could anyway be produced fairly easily. Apparently you have to use the right kind of rivets to avoid corrosion.
A lot of things could be done if the STC process was amenable.
I have done a lot of machining of magnesium in my workshop.
It is a rather over-rated material. For sure it is very light per volume, so everybody thinks it is amazing when they pick up a chunk of it, but it is also really weak. It works where you naturally want a large/thick structure for some reason (rigidity might be one) and then it will be a lot lighter than aluminium. But for anything thin it is useless. Higher-end laptops have their cases made from a magnesium alloy which is stiffer while still light, but whatever you do you are stuck with the corrosion issue. And if you drop a laptop, you will smash it up anyway. You can have a block of magnesium just sitting there in your house (dry and warm) and a few years later there is a 1cm deep hole of corrosion. So it has to be painted and the paint has to be really good. With a lot of the paintwork quality one sees in GA (even TBMs have had paint peeling off in big chunks off their wings, near the filler caps) the stuff wouldn’t last longer than weeks.
Hence I wonder why it was used on aircraft. It is surely not necessary. After all, you can install TKS panels on the leading edge of the horizontal stabiliser and you just re-balance the thing and it flies just the same.
Titanium is OTOH a really amazing material. Perhaps one could use it for the skin? I know you can use titanium fasteners (bolts and rivets) on control surfaces, where you have to add extra ones for some reason but overall weight has to be preserved.
A while ago I read about the recreation of the Bugatti Aérolithe. They described how difficult it was to shape this material. Apparently I did distort over night if not heated to the exact temperature before forming etc. So the shop which did this project should be able to build nearly any shape out of magnesium. Not sure about certification though…
RobertL18C wrote:
and at altitude around 165KTAS
Spot on….on a recent trip @ 8.5k, LOP, fuel burn of 11.2 Imp/Hour, I averaged a ground speed of 178kts, TAS 183kts.
I was very pleased with that performance considering I fly @65%. We did have a tailwind, but still….
RobertL18C wrote:
very good take off performance,
Yes she certainly climbs very well, again @104. I fly her by the book, like a mini airliner and she delivers every time. Consistent, speed and comfort. So after rotation I bring the engine back and I climb @ 25/25 boxed, then cruise @ 23 MP, 20.5 RPM. Seems to work and really suit this engine which remains as smooth as silk. its got 1380 hrs, top end @ 840.
@BeechBaby you were ahead of the curve, the -470N is becoming power plant of choice for the pre -520 35-33 Debonair series. With a three blade propeller your V-tail must have very good take off performance, and at altitude around 165KTAS?
