Month: November 2011

Pros and Cons of the Falcon 4 Stroke Paramotor Trike

The Falcon 4 Stroke … My “Sky Harley”

A couple of years ago I traded in a beloved Simonini Trike Buggy and became the proud owner of a Briggs and Stratton Trike buggy. The 4 stroke power plant was designed and built by Terry Lutke and the Flexfoil Trike was developed for PPG by Chad Bastion.   Last year I traded in my 23 horse Briggs  and Terry built  me a Falcon powered by a Generac 32 hp  with a 65 inch GSC triple prop..  The increased thrust more than made up for the increase in weight and and the climb rate increased from an average 125 ft/min to well over 300 ft/min.  After more than 100 hours it is still performing flawlessly.
In process …note the low center of gravity

Unlike the Trike buggy that had the “Power Pod and Cage” bolted on,  the Falcon is a “one piece construction” of all mild steel.  With one piece welded trike…frame… and cage … there are very few connections to work loose.  The motor mounts have been checked regularly but have never needed to be tightened.  The bucket seat is also bolted on but has remained tight.  On a couple of occasions I have had spectacular crashes that would have destroyed most paramotors but without exception the mild steel bent rather than broke and it was always an easy fix.  Either a few minutes with a bicycle frame bending tool or some quick welding.  When a section had to be replaced the raw material was easily obtained at Home Depot.

The biggest downside to going 4 stroke is the lack of fun things to do while not flying. Having spent the last 7 years immersed in this sport, I was comfortable with all the the wonderful little things that are a normal part of a PPG pilots life. The nights spent in the garage replacing compression springs or driving to the airport after dinner to pick up AV Gas. If I wasn’t searching the Internet for the best buy on Castrol TTS, I was waiting for the UPS man to deliver a 160 dollar starter sprocket. I was either working on the machine or flying it.
For every minute in the air there was an equal or greater amount of time occupied with the care and feeding of my 2 stroke paramotor. If it was blowing too hard to fly…no problem, I always had a carburetor to rebuild or a pull start that needed maintenance..

Reliable

The heart of the Falcon is a Generac, OHVI  4 stroke motor. Thousands of these motors are built every year and the economy of scale makes it possible to produce a very affordable motor with excellent manufacturing tolerances and a beautiful fit and finish. They are designed to run thousands of hours at peak horsepower, so it’s not unreasonable to expect to fly hundreds of hours with nothing more than an annual check-up and oil change. When necessary, parts and expert service are readily available at the local lawnmower repair. Gone are countless hours tinkering with the machine. No mixing fuel, exotic tools or translating owners manuals. Now ,when it’s too windy to fly, the best I can do is wish for better air. You still have to be ready for a “motor out” and have an emergency landing site within the glide slope but the reliability of this motor instills a confidence that allows for flights that would not have attempted before.
Quiet

When it is flyable, the Falcon is always ready to go and the first thing you notice is the happy rumble of the Generac. On my first flight it was so quiet that I completely forgot the step where I put in the ear plugs and put on the helmet. I realized my mistake just as I was taking off and few seconds later so did everyone at the Salton Sea when my ball cap went through the prop. …..WAAK….ear protection is still necessary but with a four stroke power plant, noise is reduced by thirty percent or more. At cruise with the RPM’s reduced it is possible to have a cell phone conversation.

Smooth

The next thing you notice is that the Generac doesn’t suffer from the constant vibration that plagues two stroke motors. With a well balanced prop  its possible to forget all about the power plant and enjoy the ride.  Flying a two stroke I was often ready to land at 45 minutes or an hour. Without the vibration I’m much more relaxed and feel like I’ll be able to fly as long as the gas and weather will permit. Cross country flights of 100 miles or more are certainly possible.

Now for the cons…
First…There isn’t the instant power you get with a two stroke.   The big prop takes longer to wrap up and you can’t modulate the throttle like you can with a two stroke.  It is still possible to fly the contour of of the dunes but you have to anticipate the power requirements and use the brakes very carefully to get that extra little bit of lift when you need it. 
It is not as agile or sporty but the more I fly the less I care to pull hard banking wingovers or swoop dive.  Another thing is the all up weight is almost 400 pounds and without going to a huge tandem wing, its way over placard.  I have no doubt that the wing can handle it but the brakes require more pressure and it will probable shorten the normal lifespan of the wing. 
Take offs are faster and require more runway.  You give up some flexibility when you go from foot launch to trike and you give up a little more when you go from a light trike to a heavy one.  The days of pulling off the highway and launching on a whim are not gone … But  … the opportunities are few and far between.  At the least you have too look a little harder for an LZ.  The trike itself is stable on the ground at high speed but trying to launch from a bumpy horse pasture can be a challenge, especially when a bump pops you up a little too soon.   My most spectacular crash occurred when I was launching at Bubba’s “High Altitude Fly In” and was popped up at high speed, but… not high enough.  When the trike came back down I was not perfectly aligned causing a roll on two axis.  The buggy was slammed hard but the damage was minimal.  It bent but did not brake. 

The Falcon isn’t the perfect paramotor but it is certainly the champ when it comes to affordability …. reliability …and comfort. 

#527 Powered Paragliding in Turbulence Tonight

 I got to the field a little earlier this time.  There was a very light breeze from the East (Weather Underground predicted.)  While I was unloading the rig, the wind shifted to the West and increased to 8 knots. ( THIS WAS A 180 DEGREE SHIFT)  It didn’t feel like a good time to launch so I hauled my wing out to the center of the field south of the runway and kited for a bit.  The Eden III was dancing overhead, there was plenty of lift but it kept shifting 30 degrees from left to right.   I had no trouble keeping it up  but it wasn’t a stable air mass.  It continued to build with gusts every few minutes,  the air was bouncing between 6 and 12 knots and continued to vacillate.  It was not looking good.   There was a band of clouds running along the front range (mountain wave). There were also large lenticular clouds East of the wave that that I thought might indicate high winds aloft.  Whatever it was… the sky was not settled and I wasn’t comfortable.
I  didn’t think I was going to launch… but hope springs eternal.  The sun was behind the cloud band and I thought there might be a chance that when it dropped below the band that there would be a favorable change.  Sure enough it did… it was still from the West but it decreased slightly and the gusts were coming down.  I had walked back to the truck and was still uncertain…. So I loaded the kiting harness and powered out to where I had left the wing, that was built into a nice wall.  If I wasn’t going to fly at least I could get some good kiting in.  Picking my way around the swoopers sandpit I drove out to the wing.  The wind was manageable but I was still concerned about gusts.  Taking extra care I hooked-in, this time making sure that the the trim cam was above the hang point loops and not likely to slip and get caught hanging the trike from the cam buckle.
Beaver moon over the runway
The launch was clean,  I did use brakes to get a little extra lift but quickly let them go and was climbing at 200 ft/minute.  The air was unstable with pockets of lift and sink.  The wing was surging and the wind speed was increasing with every foot of altitude. At 400 feet it was 20 knots and at 600 feet it was over 30.  I was glad to have flown but it wasn’t a lot of fun. I was barely penetrating into the wind and being blown way over the hangers every time I turned downwind.  Eventually I was caught in some nasty turbulence and decided enough was enough.  Turning East I set up for final over the truck.  Decent was almost vertical and the touchdown was light as a feather.  I let the wing fly after shutting down the motor and kited from my seat for a couple of minutes.  If only the air had been as stable at altitude as it was at the surface.

Short but Satisfactory 

Opps … Powered paragliding with the risers out of balance.

#525 and #526
Risers out of balance causes right hand turn
Daylight Savings changed to winter mode weekend  so….  I was a little off when planning what time to leave the house.  I could have tried the Saint Mary’s site, its only a mile away, but I wanted a long runway with a smooth surface.  The rows of bumpy ruts and high tension wires at Saint Mary’s just didn’t suit me tonight… I needed a nice easy LZ.  Vance Brand was looking good, I arrived at 4:00 pm and wasted no time putting up the wind sock and and unloading the Falcon.  It was 40 degrees, not quite cold enough to warrant the Electric G gloves but I wanted to try them out so that this winter, when it really got cold,  I would be familiar with all the hook ins and where they went..  By the time I was ready to launch it was 30 minutes till sundown. 
The wind was light from the south, not unusual for this time of day but it was the first time I’d launched to the south at Vance Brand.  I layed the wing on my lap and powered to the north end of the LZ about 50 feet from the General Aviation runway.  There was plenty of room but with the Eden III lots of runway is a good thing.  The G-gloves were bulky but manageable when I was positioning my hands to hold the the A mallions for inflation.  The wing came up quickly … I added some brake to allow time for the trike to catch up and started my run out.  The takeoff was sluggish and I found myself turning to the right.  Even at full power I wasn’t gaining altitude and a couple of times I considered. aborting but I had turned 180 degrees and was flying toward the runway. 
The correct thing would have been to go with the turn but I decided to fight it and kept adding left brake until I was able to fly straight.  Eventually I was pointed at the west end of the runway and then turning back toward the truck.  The wing was climbing but slowly.  I looked and knew there was something wrong that was causing the turn but I didn’t catch it until I landed. 

Despite being aware of keeping the trimmer cams above the hang point loops while setting up, the right side had somehow slipped down, hanging the trike from the hang point loop and the cam.  This has happened to me before and a couple of times I was able to free the cam but for some reason perhaps the bad light and dark sunglasses I didn’t see the problem. It is not a good thing, the hang point loop isn’t designed to take a load and when the cam is caught below the steel ring it causes the risers to be off center by more than an inch.  The wing will naturally cause a turn forcing me to used brakes and lose energy to maintain a straight line.  Perhaps it happened when I was adjusting the wing or positioning the lines…. whatever the cause, I was having to use lots of left brake to fly straight and when it was time to land I was using a huge amount of brake on the left side to maintain.  It is a small wing and needs speed to fly so I was a a distinct disadvantage, being forced warp the wing into an inefficient configuration to remain aloft.  The Eden riser is different from the PowerPlay,  it is more apt to do this and so I’m going to have to make it one of the last checks before starting the motor, expecially when I fly the Eden.

The second flight was just to prove I could. 
Take off was fine but the climb out was slow.  When flying the Eden I’ll have to allow for more room to gain take off speed.  The place where I had set up was adequate but there wasn’t a lot of room for error,  I found myself using brakes to get off and then I  had to stay on them to avoid dropping down.  Eventually I was stable I let up the brakes which allowed the wing to climb and the climb was good.   I circled up to 400 feet and pulled a couple of wing overs, circled over the hangers and landed.  It was all good and the landing was clean.
Two short flights…… Not much airtime… But
I got my fix and feel much better about
Life, the Universe, and Everything.