skypics added a topic in Avid fox flyers pics and vidsUnder Chamber dragHey Avideers:
Haven't visited in a long while and would like to direct Avid Flyer owners to a video I have on You Tube.
There has been much discussion as to how much drag is caused by the under-chambered wing on the Avids. So I did some tests with yarn trails under the wing especially at the front strut connection to the wing.
As you will see on the video, the yarn tells fly smoothly to the rear on take off at a high angle of attack, but as soo as I start to level out the yarn tells actually turn and face FORWARD.
I kludged up a strut to wing fairing and as you will see on the video this minimized the under wing turbulence. I am not that skilled at fabrication so I didn't install them permanently on my Model B or on my current MK4, but am have yet to put them on my MK4, but may do so soon.
Also, I need to put the yarn tells all along the underside of the wing to see if this turbulence is just at the strut or all along the wing.
These tests were done( on my model B which has since been totaled on a back country strip. I now fly a MK4.
It is quite obvious that proper wing/strut faring would substantially reduce some drag and give a few more nano knots of speed.
(See You Tube Skypics234 for video)
skypics234 at aol.com
- 3 replies
- 206 views
skypics added a topic in Avidfoxflyers General HangarConversion from Bat wing to sytraight trailing edgeAvideers:
After putting on 4200 hours on my madel B STOL with the bat wing design I have decided to recover my wings.
The fabric has been on the Avid since its inception in 1988. I did not build it.
After removing the fabris I noticed the great workmanship the Craig Johnson put into it.
A friend who is very good at working with fabiric airplanes is doing the work and is using the Stewart System
I always wondered why my fabric would be so loose in colder weather and when I took off the fabric I could see why. The trailing edge wire had gotten loose over the yeras.
We are going to put aluminum trailing edges on to replace the wire.
It is amazing how much wing surface this change will add.
I am anxious to see if there is any positive performance changes.
I'll let this forum know one way or the other.
- 3 replies
- 462 views
skypics added a topic in Introduce yourselfI'm new to this forumMy name is John. I have owned an Avid model B STOL since 1990 and hav flow in for 4150 hours so far.
I have been through 5 different engines. 1) Rotax 532 with rope start 2 & 3) Rotax 582s 4 & 5) Jabiru 2200.
The 532 was swapped for the 1st 582 for the dual ignition feature. The 1st 582 had no starter so I hand propped it. The 2nd 582 had an E box with starter.
I wanted a 4 stroke and installed the 1st Jabiru 2200. They had just changed to hyd lifters and the engine had many issues and problems. I had it rebuilt after an exhaust valved head popped and destroyed the number 2 piston, head rod, etc. My dealer replaced the bad stuff and rebuilt it.
After getting it back from him I fired it up and it threw a rod. I was pissed as you might imagine.
I contacted the dealer and he said he would provide me with a brand new , up to date Jab 2200 if only I wouldn't publish my experience on the Jabiru forum. I agreed and have been well pleased with this latest engine. I have flown it for 850 hours with nary a hick-up.
I did not build my Avid, but I have modified it to make it all that it can be.
Removed the panel tank. Don't like gas hanging over my legs. It still carries 28 gallons in the wings.
Removed the flberglass bucket seats and replaced with the sling seat
Moved the rudder peddals forward 3 inches.
Added extensions on the elevators for better pitch authority
Split the windshield. Now it has a clear .060 front Lexan and a .125 tinted top glass.
Changed the 600 x 6 tires for 800 x 6 x 21" Tundras for that back country flying.
Installed a leaning device similar to HacMan for the Bing carb.
Installed a vacuum gauge similar to that used on autos to monitor my engine health.
Installed VGs which gave much lower stall with flaperons OFF and some benefit with flaperons ON.
Installed VGs on pilot side of the vertical stab to compensate for the vert stab offset designed for the Rotax spinning the other direction.
Installed gap seals on horizontal surfaces
Installed fairings in jury struts, horizontal lift struts and tubes that go from the bungied to the axels.
Installed a Dynon D6 for those times when you wish you had gyros on board.
Installed fuel flow meter
My Avid cruises at 100-105 TAS running 2900 RPM burning 2.8 GPH. Range is about 10 hours or 1000 miles...cough...cough. Bladder range is 3 hours.
Climb is 1000-1400 FPM depending on load and DA.
The Avid was built in 1988 by Craig Johnson
- 6 replies
- 820 views