View Full Version : View From a GyroBee Seat
04-26-2004, 06:45 PM
The picture below is the view from the seat of my GyroBee while cruising at ~650' MSL (600' AGL) over farm fields of the Skagit Valley in western Washington state yesterday afternoon. Careful observers will note I had a 7 mph tail wind.
That's Interstate 5 in the distance which runs from Canada all the way down to Mexico.
Outside of Holland, the Skagit Valley is the world's largest producer of Tulip flowers and bulbs. The tulip flowers and bulbs have just been recently harvested, and you see a couple of bare fields. Several weeks earlier the fields were colorful... but I missed it being on vacation in beautiful Death Valley, CA! :)
04-26-2004, 07:36 PM
Those EGT readings are too cold. Be looking for excessive carbon build up.
04-26-2004, 07:58 PM
You're right Ron... the EGT's are a tad on the cool side and I do need to change the main jets down a step. I had the carbs jetted for cooler weather and hadn't gotten around to swapping them out.
That said, I prefer to err on the rich side and I do a complete disassembly and de-carbon every 75 to 100 hours anyway. When it only costs $120 for a complete gasket and seal set... I figure why not? It makes a nice winter weekend project.
04-26-2004, 08:25 PM
What throttle position(% 0-100) were you at when the pic was taken? How are the new shocks working out?
04-27-2004, 06:57 AM
What throttle position(% 0-100) were you at when the pic was taken?Boy Ron,
I'm afraid I can't tell you because it's not something I pay much attention to. There was lots of throttle movement left.
If it helps, here's more information...
That day it was about 60-65 degrees OAT at altitude, and to hold 50 mph indicated, it took about 5,500 engine rpm. The airspeed dropped a bit for the picture because I was distracted while fiddling with the camera and also flying through some up/down drafts. At full power (6,300 engine rpm) and about 45-50 mph I was getting an 800 fpm climb rate on the VSI. This is with a dual-carb Rotax 503, 2.58:1 B gearbox, a 3-bladed 60" Ivoprop and 540 pound takeoff weight.
How are the new shocks working out?Just great. I've been carefully working into some mild "stop-and-drop" type landings with them, and so far I've plopped the gyro down on the runway a couple of times from a dead stop at about 1 foot AGL. The resulting landing is nice and smooth. It's quite fun.
The only thing I've had to adjust to is that takeoffs still feel a little less "defined" when the main wheels leave the ground. What I mean is... I think as the gyro leaves the ground, the shocks extend considerably keeping the main wheels in contact with the runway longer. In other words, the gyro is actually flying but the main wheels are still momentarily in contact with the runway. The gyro is trying to do the "torque wiggle" at the same time and it just feels a little sloppy compared to the former landing gear with it's shorter travel. I think I just need to get out and practice several hours of stop-and-go landings to get used to the feel and refine my technique. So far this season I've been having too much fun sight-seeing and cross country flying to get down to basics... which I better do soon before the airshow season approaches!
04-27-2004, 08:51 AM
04-27-2004, 08:59 AM
Sorry, my 2 stroke tuning gene was kicking in. I am sure you are aware of all this but I have lost track of the number of 2 stroke motorcycle problems I have troubleshot for misjetting, such as: Only putting in new larger mainjets with a new exhaust system install and wondering why the engine siezed while cruising down the highway at 1/8th throttle.
I was just curious when you said you were thinking about changing the main jets down a bit based on those cooler EGT readings. I recall you saying you run fairly large throttle settings even in cruise but is it possible that your throttle was less than 3/4 open? 1/4-3/4 throttle mixture is controlled by the needle jet/jet needle combo. If you were at less than 3/4 throttle then you might want to consider lowering the needles a notch first to lean out that throttle region.
How are the EGT's at full throttle? 3/4-full throttle mix is controlled by the main jet. Personally I would select a main jet that gave a good reliable running temp at the FULL throttle position.
Again I am sure you know all this and if so I appologize, but it would have kept nagging at me untill I said something. Since you said you were not sure of where the throttle was, it might be something to check on your next flight.
Thanks for the shock update. I could see a high "stop and drop" tollerance(without rebound of course:) being a very usefull assett in an emergency landing as well as giving a larger margine for error during planned arrivals.
Love your always informative updates, Thanks
04-27-2004, 09:48 AM
Thanks for your comments. Good warnings.
When I said "lots of throttle left," I can see how that might have worried you. If I had to guess, I'd say at cruise (5,500 to 5,700 rpm), the throttle is at least 75% power and solidly into the main jets.
And the EGT's don't get much hotter at full power... they do climb but stay still well in the green arc. I don't ever remember getting worried about the EGT at full power. But I can't tell you the exact EGT temps at full power because not only to they vary with the OAT, but I don't memorize that kind of stuff (as long as they are in the high side of the green arc and the engine is running fine). The good news is my plugs look normal.
Again, I tend to err on the side of caution with a normal to slightly rich mixture. I usually run stock main jetting until well into the heat of summer (like 90 degrees) and then I change to the next size leaner main jet. I adjust the idle mixture 3 or 4 times per year as the conditions change (it's due for an adjustment again as the last time was in February).
I don't like to play around and push the EGT's up too much. My engine runs absolutely great and I'm currently getting good fuel economy. I also don't trust the EGT gauge readings enough to want to risk melting something. Instead of searching for the perfect EGT reading, I'd rather just deal with any carbon buildup in the cylinders during the winter maintenance.
Now if I could modify my Rotax 503 with fuel injection... that would be the ticket! :) I did look at those altitude compensating carb kits you can buy, but for the low altitude / temp changes I generally operate at, I decided it wasn't worth the expense or trouble setting up.
There's definitely something to be said for keeping things simple. If it ain't broke...
Well I think you know how the saying goes.
04-27-2004, 10:00 AM
Good to hear the shocks are working for you. I'm curious, have you noticed any adverse steering or handling problems since you shortened the width of the gear? Does it handle better, worse or no different?
04-27-2004, 11:35 AM
I'm curious, have you noticed any adverse steering or handling problems since you shortened the width of the gear? Does it handle better, worse or no different?Takeoffs / landings seems no different at all to me with the landing gear narrowed to 70" wide overall. I honestly can't tell the difference. Ground handling seems about the same as before too.
I suppose I lost a little bit of the turning radius while taxiing, but it was so tight to begin with, that even though I may have lost some, it doesn't matter. I can still make a u-turn on a narrow taxiway.
So basically I haven't uncovered any negatives so far... but I'm looking for them and would let you know.
04-27-2004, 04:18 PM
John for someone who likes to keep it simple.... You about floored me when I saw that you made and installed a catch tank for the fuel pump weep hole!!! I am just teasing you, but WOW that ain't exactly keeping it simple!
04-28-2004, 06:46 AM
...but WOW that ain't exactly keeping it simple!Oh contrar Ronny... that one time modification makes keeping my gyro clean *very* simple! :)
04-28-2004, 05:54 PM
Ok! I got ya.....
04-29-2004, 04:55 AM
I would have raised the pump!!!!!!
04-29-2004, 09:31 AM
I would have raised the pump!!!!!!Or maybe lowered the airframe.
Ray Mohammed Al
05-20-2013, 10:11 PM
can I use a motorcycle engine ( one piston) 150cc for a gyrobee
05-21-2013, 03:35 AM
Sorry Ray, that wouldn't be enough power to fly any gyro I know of. You seem like you have an engine and a desire to fly. The choices you will have for an engine like that are a powered backpack parachute, a small powered hang glider/trike, or a fixed wing plane. Gyros and helicopters are not efficient machines and need much more power to fly.
Maybe you should think of what aeroplane building materials you have available or want to work with to narrow down the choices of plane to build. Generally it is aluminum tube and dacron fabric, high quality very thin plywood, fiberglass and epoxy, and thin sheet aluminum.
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