Saturday, March 29, 2014

Do not forget to fly

Finally good weather here, and I have been doing some flying. It is very easy to forget about flying when building, but keeping current is important when the big day arrives. My gliding club has got a new tow plane. We had a Piper Pawnee that was a pure joy to fly, but now we have a Aerospool WT9 Dynamic. The WT9 is still being used for check rides to get enough current tow pilots on the type, so we had to rent a 180 HP Super Cub for a few weeks. I spent a couple of days tugging gliders this weekend. I have also been taking some gliding lessons,.














Saturday, March 22, 2014

Engine

Watched/listened to the webcast from Sonex about the Aerovee engine.Very interesting to see how it became the engine it is today, and why it is a kit, not a finished engine. However, the lack of anything that can be called engineering in that engine, is all too obvious. All in all; a bit disappointing, still I am left with the impression that the engine is well tested in the field, the complete package is well thought through functionality vise, and that the engine will do what it is supposed to do. A good engine for the Onex? Yes.

Avgas UL91 is coming. Basically it is unleaded avgas 100LL and with octane numbers of 91 MON, 96 RON (whatever that actually means). Statoil is starting to sell this fuel in Norway. Avgas 91 UL is for all practical purposes aviation quality Mogas, and that can only be a good thing. The ability of the engine to run on UL91 is yet another additional important factor.

Name Type HP(max) RPM(max) cc kg Price € TBO [H] UL91 Mogas
Rotax 912 UL 80 2200 1300 72 € 12 142 2 000 Y 95
Rotax 912 ULS 100 2200 1400 75 € 13 499 2 000 Y 95
Rotax 912iS 100 2200 1400 75 € 18 329 2 000 Y 95
Sauer 1800 UL 68 3200 1835 64 € 7 845 1 600 Y 95
Sauer 2200 UL 85 3000 2234 66 € 9 567 1 600 Y 98
Sauer 2400 UL 100 3500 2332 75 € 10 574 1 600 Y 95
Sauer S 2100 ULT 110 3000 2161 76 € 13 586 1 600 Y 98
Limbach L2400 EFI 100 3000 2424 76 € 23 900 1 600 TBD 98
D-Motor LF26 92 3000 2690 57 € 12 600 1 500 Y 95
ULPower 260i 97 3300 2592 72 € 14 700 1 500 Y 95
ULPower 260iS 107 3300 2592 72 € 15 800 1 500 Y 98
D-Motor LF39 130 3000 3993 79 € 17 800 1 500 Y 95
ULPower 350i 118 3300 3503 78 € 18 800 1 500 Y 95
Limbach L2400 EB 84 3200 2424 82 € 19 500 1 400 TBD 98
Revmaster 2300 85 3200 2331 77 € 5 729 1 200 TBD 98*
Verner Scarlet 7H 110 3500 4127 82 € 11 990 600 Y 95
Hummel 2400 85 3600 2400 76 € 4 850 0 TBD 98*
AeroVee 2.1 80 3400 2180 73 € 5 083 0 TBD 98*
Great Plains 2300 80 3600 2276 75 € 5 199 0 TBD 98*
AeroVee 2.2T 100 3400 2180 80 € 7 266 0 TBD TBD
Viking Honda 110 2300 1500 81 € 9 439 0 TBD 98
Jabiru 2200 85 3300 2200 64 € 11 263 0 Y 95
Jabiru 3300 120 3300 3300 84 € 14 460 0 Y 95

* with reduced compression ratio, and thus reduced HP and efficiency.

A tiny bit too early for a conclusion. But the Rotax, D-motor, Viking, Limbach, Verner is realistically no longer options for me. It will be too much work to redesign everything firewall FWD. Limbach is too costly etc. From the other manufacturers I have received very positive correspondence about how to proceed and what kind of help I can expect. Sauer will be a drop-in replacement, with only minor modifications. ULPower have a guy selling motor mounts, etc. The list is therefore shortened to:

Name Type HP(max) RPM(max) cc kg Price € TBO [H] UL91 Mogas
Sauer 2200 UL 85 3000 2234 66 € 9 567 1 600 Y 98
Sauer 2400 UL 100 3500 2332 75 € 10 574 1 600 Y 95
ULPower 260i 97 3300 2592 72 € 14 700 1 500 Y 95
ULPower 260iS 107 3300 2592 72 € 15 800 1 500 Y 98
ULPower 350i 118 3300 3503 78 € 18 800 1 500 Y 95
Revmaster 2300 85 3200 2331 77 € 5 729 1 200 TBD 98*
AeroVee 2.1 80 3400 2180 73 € 5 083 0 TBD 98*
Great Plains 2300 80 3600 2276 75 € 5 199 0 TBD 98*
AeroVee 2.2T 100 3400 2180 80 € 7 266 0 TBD TBD
Jabiru 3300 120 3300 3300 84 € 14 460 0 Y 95

To achieve 80/85 HP on the american VW conversions, I will have to use 100LL. A fuel that may not be available for much longer. All the other engines runs equally well on UL91 and Mogas.

Thursday, March 20, 2014

Left wing and rear mid spar

Drilled and riveted in the left side angle bracket that were wrong, and riveted on the rear spar.


Then I remembered I have one more spar, the rear mid spar. Drilling, deburring and started stacking. The outer spars are going to slide into the mid spar. It will be interesting to see how that works out when Sonex had no measurements to give out when the brackets had to change.


Left wing

Fixed the remaining two ribs and the aileron paddle


Monday, March 17, 2014

Left wing

Riveted together the inner most rib doublers and bracket. Riveted on the outer ribs.


Sunday, March 16, 2014

Left wing and the ONX-W10-03 fix

Continued on the left wing. Countersinking holes and riveting aileron brackets. Finally received the angle stock from ACS, and made new angles for the aft main spar according to this from Sonex aircraft. The description from Sonex of what is wrong and how the parts are to go together to make it right is nonexistent, and the drawings give no dimensions whatsoever. Sonex isn't even willing to send me new correct parts. Really disappointing.

The error is the pilot holes in the angle is too far down so the aft spar will be mounted too high. The result in the skin will not fit. With the new angle made, it is easy to get the rear spar to fit using some aluminium strips. The problem is getting the dimension along the aft spar correct. I used the bolt holes for the original angles, since there are no dimensions in the drawings.





Thursday, March 13, 2014

Main spar

The last 1 inch rivet in place. The spot is when I tried to clean the primed spar with some new silicone remover, not a good idea.


Tuesday, March 11, 2014

Main spar

Even with the C-frame on the concrete floor, the manufactured head did not set properly on the 1 inch rivets. The fastest way, by far, was to use a large and heavy and long bucking bar and the rivet gun on all rivets. With the long bar it was much easier to get the shop head straight compared with the small tungsten bar. The difficult part with this was to push hard enough on the rivet gun. Have to remember this the next time I make a main spar :-)

Monday, March 10, 2014

Riveting the main spar

Clecoed together the spar with the steel parts just to make sure the bolts would go in right. Then I removed the steel.

Started riveting with the C-frame on the concrete floor, but my back said "no". So continued on the table. For the smaller rivets all went fine.




The the -16 rivets also seemingly went fine until I I looked on the manufactured head. They were not set properly, large gaps between the head and the angle. Just not enough metal in the C-frame for these long rivets.


Had to drill them out. Then continue by hand with the rivet gun and the Tungsten bucking bar. A bit difficult to get the same consistency on the shop head by hand compared to the C-frame on these large and long rivets, but OK enough, and the manufactured head is totally flush.


Wednesday, March 05, 2014

Main spar primed

Deburred and primed the main spar, also the steel parts. I leave it to cure overnight.


Sunday, March 02, 2014

Main spar

Finally finished with all the holes in the main mid spar including all the steel parts. Priming and riveting next. It's a lot of work with a surprisingly large amount of parts that together constitute the main mid spar in an intricate but well thought out manner. The folding mechanism also makes a lot of parts. A drill press would probably speed up the work a lot, and the pre-made spar option is probably a good choice also.  


Saturday, March 01, 2014

New controller

In Norway we need to have controllers appointed by Luftfartstilsynet. Their job is to sign the build log and to give advice and help. The build log is a document that is to follow the aircraft through it's lifetime, it's the documentation that all parts are OK. It's a way of quality assurance of the build process and the finished parts. I think this build log is a very good thing, particularly when selling/buying used experimental aircraft. I would never dream of buying a used experimental from the US, where there is no requirement to document the build process.

My old controller moved to another part of the country. I couldn't close up the structure, horizontal and vertical tail surfaces, before the controller had inspected and signed off. I have used some time to find a new one, but when I finally got a new one, he happened to live only a couple of hundred meters from my home. So finally I can close up stuff and be finished with pieces.   

Engines

Which engine to get is a hard nut to crack. I have updated my list and also included TBO. The reason is that the geography in Norway is very different from the European or American mainland. Good emergency landing spaces are far apart, 99% of the country is either woods, mountains or water, and none of those are good places to land in an emergency. I have to be somewhat lucky to survive, very lucky not to be injured and extremely lucky not to wreck the aircraft. Having flown only in Norway, mostly with certified Lycoming/Continentals or the ever-running Rotax, I haven't given it that much thought until I the engine stopped in a Piper Pawnee last year. I was extremely lucky to be able to glide back to the airfield and make a good power off landing with no damage whatsoever, but will I ever be that lucky again? From a practical point of view surviveability is handled in one of three ways for a single engine aircraft.

  1. A very reliable engine.
  2. Low impact velocity and or low kinetic energy (low stall speed and low weight).
  3. Emergency ballistic system or parachute.
It is obvious from the above list that the single most important factor to protect pilot and airplane is a reliable engine combined with good airmanship (always look for emergency landing spots etc). 2 will most certainly help regarding both surviveability and damage to the aircraft if the engine stops. The Onex do not have a particularly low stall speed, but the weight is low. Number 3 I am not sure is such a good idea at all in relation to the risk of engine stopping. I see 3 as a solution to other cases such as the risk of colliding in gliders or perhaps mechanical failure of the aircraft structure when doing aerobatics.

The only meaningful obtainable number regarding the reliability of an aircraft engine is the TBO. TBO is not the same as MTTF, but it is correlated. A set TBO means the MTTF is well within acceptable limits, if the engine is maintained properly and is operated within the TBO. My general experience also suggests that Lycoming, Continental and Rotax are extremely reliable engines, and these three all have a TBO of 2000+ hours.

With this in mind, the choice of engine becomes more interesting. TBO will be a number to take into consideration. Originally my position was to find an alternative to the Aerovee, one that was not too costly and one that I didn't have to put together myself. Today my position is in fact to find good and relevant reasons (excuses?) for not installing a Rotax 912. This means my engine alternatives have changed and have narrowed down to Rotax, Sauer and ULPower with Jabiru 2200/3300 as possible options.

Name Type HP(max) RPM(max) cc kg Price € TBO [H]
Rotax 912 UL 80 2200 1300 72 € 12 142 2 000
Rotax 912 ULS 100 2200 1400 75 € 13 499 2 000
Rotax 912iS 100 2200 1400 75 € 18 329 2 000
Sauer 1800 UL 68 3200 1835 64 € 7 845 1 600
Sauer 2200 UL 85 3000 2234 66 € 9 567 1 600
Sauer 2400 UL 100 3500 2332 75 € 10 574 1 600
Sauer S 2100 ULT 110 3000 2161 76 € 13 586 1 600
Limbach L2400 EFI 100 3000 2424 76 € 23 900 1 600
D-Motor LF26 92 3000 2690 57 € 12 600 1 500
ULPower 260i 97 3300 2592 72 € 14 700 1 500
ULPower 260iS 107 3300 2592 72 € 15 800 1 500
D-Motor LF39 130 3000 3993 79 € 17 800 1 500
ULPower 350i 118 3300 3503 78 € 18 800 1 500
Limbach L2400 EB 84 3200 2424 82 € 19 500 1 400
Verner Scarlet 7H 110 3500 4127 82 € 11 990 600
Hummel 2400 85 3600 2400 76 € 4 850 0
AeroVee 2.1 80 3400 2180 73 € 5 083 0
Great Plains 2300 80 3600 2276 75 € 5 199 0
Revmaster 2300 85 3200 2331 77 € 5 729 0
AeroVee 2.2T 100 3400 2180 80 € 7 266 0
Viking Honda 110 2300 1500 81 € 9 439 0
Jabiru 2200 85 3300 2200 64 € 11 263 0
Jabiru 3300 120 3300 3300 84 € 14 460 0

Engines with no TBO (zero TBO) runs in a state of "on condition". This is the same state as a Lycoming/Rotax that has exceeded its TBO runs in. What does this really mean? Well, this is basic maintenance and reliability theories in action in real life. An engine that runs within its TBO has an MTTF or MTBF that is constant and known. That is, as long as the engine is operated and maintained according to the factory documents,  the failure modes are known and happens so seldom that the risk is acceptable. The risk of sudden catastrophic failure of the engine parts (considering everything else is OK) is non existent from a practical point of view. When exceeding the TBO, the wear and tear on the engine starts to affect the reliability and any number of random things may happen at any time.

A TBO assures the engine will be reliable within its TBO, with a predetermined and very specific set of maintenance. With no TBO the engine can also be just as reliable, theoretically, but you have no idea what kind of maintenance is needed, or how often you have to do it. With no TBO, it runs "on condition". For a Lycoming this is OK for a limited time because the large number of engines in operation has limited the things to look for to a few points during condition inspection. For an engine that is put together by random aftermarket auto parts with no track of the origin, you have no idea, literally. You have no idea what to look for, thus no idea how to maintain it to assure it will run without failure the next hour.

So, an engine with a TBO is a world of difference better than an engine with no TBO, anyone saying differently don't know what they are talking about. It is better because you know how to maintain it, you know what to maintain and you know when to maintain it to be sure it will run without problems the next hours.

For practical purposes this means that a VW engine wizard will have no problems operating and running a VW aero engine conversion, and it will be every bit as reliable as a Lycoming. He knows what to look for, he knows what parts are OK, which aftermarket manufacturers are OK, how long each part last and so on. He will always be one step ahead of any failure waiting to happen. Myself, I am no VW engine wizard, I am no [any engine] engine wizard. So the only way for me to achieve a reliable engine is an engine with a TBO and a specific maintenance schedule within that TBO.

More bolts in the spar

The right side. The black plastic liner is to be placed on the fwd side (obviously when thinking about it).



Except for 30 and 40 drill bits, the Drill Doctor works excellent.