Anders Stenhammar

I used a fuel refilling hose. It's reinforced and very strong. I cut it in 1" pieces, drilled two holes in them and bolted one side to the firewall and one side to the mufflers clamp.

Hi Jim.

Yes but MkIV HH have a gross of 1150lbs-1200lbs and I was hoping that was because of the 7/8" struts and more ribs, different tail feathers, gear and fuselage?

I counted the ribs on mine and there is only 9 ribs, so it seems like it's a standard STOL wing with HH spars?! I am hoping this would result in a MTOW of 1050 instead of 911 or 1150lbs. Bit of course this is only guessing and until I really know, I stick with 911lbs.

Yes I have but I haven't had it in the air yet. I am installing the battery in the tail also.

HI Doug.

My C-mod STOL has 0.083" spars and 3/4" struts.SN 466. it was built in 1992. Does that mean my MTOW is 1050lbs? Do you know of any documents that can verify this? In my Swedish papers it say MTOW is 911 but I believe that they didn't know that there also was a C HH version.

I did some  ground running today after replacing the pistons on my new to me RR670. I did this procedure: 2,5min at 2500rpm, then 5min at 4000rpm and then 6min at 5000rpm and about 10 seconds at full power. I got a little high max static rpm (6700rpm) so I will add a little pitch to get it down to 6300rpm. I also discovered that at 4500rpm the rpm was very unstable, is that because of the Rave or maybe because of the low prop loading you think?

 Below 2500rpm it is shaking quite more than the 582, is that something I will have to live with? I know I shouldn't let it go below 4000rpm during flight but sometimes I just have to go idle and wing slip to get down because the Avid Flyer is so light with high lift wing.

I just started my new Rotax Rick 670 with C-box 3:1 and 3-blade 72" Power fin. I've been running it for 1 hour now and I also think it shakes quite a lot at startup and at idle. I guess I just have to stay above 2500rpm. I will try to turn out the air idle needle.

I would love to have a clutch bit the weight penalty is not ok on my Avid Flyer mod C.

Fixed some clearance in the firewall and managed to hang the muffler.

Soon, I will join the King Kong family :-) 

I am installing my 670 right now. Need to modify the firewall a little. The mod C engine cowling is getting butched around the E-box... One day I will do some fiberglass work to fix this.

The biggest concern now is to find a way to hang the muffler in a good way.

It's crazy how there are so many different requirements from different countries to get to the same results! Sweden where I live  is one of these and often the Swedish authority just accept the modifications developed by other "respected" European countries. The UK did the same job but those mods are not as near as extensive as the Switzerland's mods. Still the UK mods are "UK certified" for the same gross weight. So if I as a Swede would want to get higher gross weight approved I would choose the UK mods to copy. 

There are as many different "load calculations" as there are aeronautical engineers !

Thanks! 

Thanks Nlappos. 

Unfortunately I am located in Sweden, so I need to fix that exhaust by myself. I have looked at it and it seems doable.

I am about to buy an RR 670 that has a Kitfox exhaust. I want to install it on my Avid Flyer C but wonder if the exhaust will fit? Anyone have any thoughts about this? 

Just wondering, how  did you rebuild your struts? I am thinking about doing the same with a pair of mine.

Hi Japowell.

How is the wing mod going? I am also about to extend my aerobat wing. I got some documents from the British LAA / PFA. Do you have any drawings or instructions for this? 

Done some improvements today. Getting ready for a cross country trip next weekend.

Ok I will do some W&B and aim for 18" CG. I have noticed that it lands better when I have weight in the cargo. 

I remodeled the hat rack today to get more space. I removed the plates and made a sling shelf that goes down just above the flaperon mixer. My dog is much happier with the bigger headroom. Now I need to unhook the ailerons when folding the wings. But with castle nut and a key ring, that's just fine.

What about the C/G when loading a bunch so far back in the fuselage? What max weight did you fly with in your B model? I have a C model and I am Always goping ower max gross when having passenger and full tank and some cargo. I fly carefully then and not pulling any G and baking not more than 30 degrees in level flight. But it would be nice to hear what others have survived , LoL.

Nice work! Like the strut fairings, I am also planning to do them. You said 120moph, thats awsome. I am working on a pair of aerobat wings for my Mod C STOL fuselage and exited to know what I will expect in performance. At what weight do you get 120mph? Is it a Rotax 582 and what max rpm do you get at climb? 

Made a shelf for our dog Molly,she  didn't like the sloping hat rack. I just taped together two lexan plates that folds out and fits on to the hat rack line a shelf. Molly loves to fly and always wear a safety belt and ear muffs. 

Finished painting my cowling now, happy with the result. It's a quick fix so it's ok. I will try to tape if the two holes under the prop and get a spinner also, guessing that will do some drag reduction also.  

Now I have removed the side mount in stainless steel parts and the side radiator cowling to loose more weight and drag. Doing some flight tests and haven't noticed any big difference but I am still happy to loose the weight and the ugly cowling.

Now it's time to sand the fiberglass sheet and paint it. Some day I might do a proper job instead of the riveting. 

I also bought a GSC 3 blade 66" prop and are wery happy with it, even though it was a pain to adjust the pitch. I had to use my smartphone with an leveling app that that 0.1 degrees resolution. 0.1 degrees at 24" out from the hub gave me about 200rpm. I set it on 6100 max static rpm and that gave me 6500rpm at climbing. Spark plugs got a light chocolate brown colour.

So great success! The belly radiator performed really good! Today's flight test had ambient temp at 16C/60F. climbing 1200fpm at 50mph and still only 75C/167F water temp! But, at cruise the temp went down to 60C/140F. I think that the next step would be to install a thermostat. 

I am very happy about this. I managed to reduce the empty weight more than 5kg/11lb of radiators, hoses and water. I also got the CG further back. 

I noticed a higher cruise and more efficient elevator and lower stall speed! This forum is great!

So now I have installed the belly radiator and removed the side radiator. I will test it this weekend. The right hose from the engine top has a T connection for the expansion bottle that also has a pressure filler cap on it. If this is not enough cooling I will mount  the rotax912 oil cooler parallel with the belly radiator. Hopefully that's not needed. 

Very nice information. I actually have one of those radiators on the shelf from an other aircraft. I will mount it and see how it goes. Just need to buy some hoses. But does the hoses go straight up to the engine or is there any filler neck cap on the way?

So now I have removed the small radiator and the WT is up at 80C at 20C ambient. 2kg lighter at the nose and a better flying aircraft. At climb I reached 90C. I guess next step would be to replace the side radiator with a belly radiator.