I hope that you find this section useful. Please feel free to reproduce these tips, all I ask is that you give credit where credit is due, i.e. acknowledge where the information came from.
(© Copyright: Skydragons Leisure Limited)

Downloads.

• Emergency parachute fitting instructions for H.R.S (pdf 1.1mb).
• PAP Top 80 owners manual.(pdf 5.6mb)
• Torque settings for Top80 engine. (pdf 0.1mb)
• PAP Ros 100/125 owners manual (pdf file 5.7mb))
• PAP Corsair M21Y owners manual. (pdf 1mb)
• PAP Corsair M25Y Black Devil owners manual. (pdf 1mb)

Engine tips.

• Starting the Top80.
• Top80 gearbox information re ratios.
• Poor starting diagnosis.

Flying tips.

• Takeoff.
• Low level flying (& problems with throttle control).

Wing tips!

• Dudek brake modification.

Starting the Top 80 engine (Standard Walbro membrane carb). (Updated Nov 2006) Do your usual pre-start safety checks. When the engine is cold (i.e. 1st start of the day) or the fuel exhausted from the tank, the carburation system will require priming. To enable this there are two devices that you will use, the first is the primer bulb to pump the fuel from the tank to the carb', the second is a hole approx. 10mm in diameter located on the propeller side of the carburettor which provides access to the fuel control valve diaphragm (annotated (B) on the attached picture). Using your fingertip or a blunt object, gently depress the diaphragm which can be seen through the hole, this way when you pump up the fuel it will vent the system of air very easily. Later versions have a button so that you don't have to insert anything into the hole. Watch for fuel passing through the clear plastic filter located in the fuel line near to the carburettor, as this will warn you that fuel is nearly at the carb. It is important to avoid pumping too much fuel into the carburettor as this will lead to flooding and in severe cases can lead to hydraulically locking up the engine or at best a "kick back" on the pull start handle as the engine fires prematurely and pulls the handle from your hand. As fuel reaches the carburettor you should feel a small movement of the diaphragm, at this point stop priming the system. (You will only feel fuel entering the carb if you have a light pressure on the diaphragm, just enough to depress it) Now move around to the harness side of the machine, apply the choke by pulling the choke activation wire(not all models have a wire, so just use the choke arm) towards the front of the machine and applying approx 5mm of throttle, pull the starter handle, if you have primed the engine correctly then the engine will start and immediately stop. Sometimes this starting of the engine is just a very easy pull of the rope and you don't always hear it run properly, so if this happens just treat it as though it has run and stopped and return the choke wire to the run position by pushing it back towards the carburettor. That done, then pull the start handle again and the engine should start. N.B. Some motors will start happily from cold wothout the use of choke, so try priming and starting without choke, if it starts then you can leave out the choke procedure.

Other tips:

a) Ensure that you are holding the machine firmly with your left hand on the frame above the start handle. Hold the frame to the ground also with your foot on the corner by the fuel tank. This is so that when you pull the start handle you have a hand above it and a foot below and this way the machine will not move when you pull the starting handle.

b) Avoid pulling the rope so strongly that you use its full length. If you do this then you will eventually break the handle, the rope and perhaps the starter mechanism.

c) Use a little squeeze of throttle when starting, by a little I mean move the throttle lever no more than 5mm, just a little pressure, then when the engine starts and runs smoothly, release the pressure to tickover position.

d) Sometimes when the weather is very cold, or the carburettor is set a little too lean, then you may have to repeat the application of the choke. This happens if on the second pull the engine starts and runs but in a short time the engine dies away and stops. So apply the choke, pull the start handle, release the choke and pull the start handle and it should run OK this time.

e) If you have pulled the starting handle 3 or maybe 4 times and the engine hasn't fired or started to run then something isn't right. Stop and think, don't just keep pulling the rope like a lunatic! Have you primed the system correctly, maybe you primed it too much and the engine is flooded. To cure this, holding the machine firmly open the throttle fully and with no choke, attempt to start the engine. If it is flooded then after the 1, 2 or 3 pulls the engine will start, there maybe a lot of smoke and quickly the engine revs will increase so once it has started be ready to quickly reduce the power setting to tickover. Next time watch the fuel going through the filter and feel for the fuel entering the carburettor
Maybe though there is not enough fuel. When this happens the engine is a little harder to turn over with the starting handle and sounds dead. Just try priming it a LITTLE more as for the engine to run there must be some fuel in the carburettor and then follow the procedure with the choke etc...

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If you are ever in the unlikely need to repair or replace the gears in the reduction drive on your PAP 1400 Top80 mahine, the first thing you need to establish is which gearbox you have, whether you have the one designed to run on "Gloopy" grease, pre Feb' 2005, or the later one designed to run on oil. The easiest way to tell the difference is by the type of gearbox breather and the case shape. The earlier model has a plain tube to act as a breather, whereas the later version has a breather device with a metallic cap on it and the case has a more rounder shape, see photos on right. Prior to Feb 2005 the factory fitted a 3.6 / 1 (20/72 teeth) reduction to standard PAP 1400 Top80 machines with an option to run a 3.9 / 1 (actually 3.84 / 1, (19/73 teeth)) with a carbon prop; thereafter all 1400 Top80 machines have been fitted with the 3.9 /1 and the wood prop spec was changed to a 53cm pitch. NOTE that the gears from the early box are not interchangeable with the later version, although if you have been running the 3.6 ratio on an early type g/box you could change to the 3.9 and change the prop, this gives improved throttling and thrust. Re seals: the early reduction (running grease) does not have a seal before the bearing on the clutch side, it relies on the seal on the bearing stopping the grease leaking onto the clutch. It does have one on the output shaft. The later gear box has a seal on the clutch side small gear shaft, this is quite difficult to replace and the factory advises that if it wasn't leaking to leave it in and only replace it if it is obviously damaged. As with the early version gearbox there is a seal on the output shaft. Please note that if you remove bearings and or seals that they should be reassembled using "Bearing fit" liquid. Also use "bearing fit" on the splines of the propeller carrier or wear will occur on the spline causing the propeller to have play in the tracking, which will lead to excess vibration.

Early style reduction gearbox on PAP 1400 Top80 machine.

Later style reduction gearbox on PAP 1400 Top80 machine.

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Flying tips.

The Takeoff - minimising the takeoff run.

There are a number of reasons why takeoffs don't happen as quickly as the pilot would like. Here are a few of the reasons and solutions.

You would be surprised at the number of pilots that don't use full power! Once the wing is correctly inflated overhead, don't delay, apply FULL POWER. Ah but I hear some of you say, "I can't use full power because my machine twists and snakes uncontrollably if I do". Sometimes tightening up the harness may help, but its a fact of life that some chassis' just aren't designed very well, the only solution is to change to a machine that is designed well, such as a PAP TEAM machine. Sorry if sounds smug but there is some rubbish being sold and it shouldn't be tolerated.

Another common reason for extended t/o runs is because the pilot isn't leaning back far enough!. Getting the thrust pointing down to some degree is a good thing, so it is important to push your shoulders back during the takeoff run. Another reason is that too much brake is being applied and this delays the wing gaining airspeed, or that no brake at all is applied and this also delays the t/o ! I suggest that if you can have someone video your t/o, then you can analyse your technique. Or if you can compress the file, e-mail it to me and I'll provide a critique for a modest fee. (A pint of beer or two!)

In the meantime you could try this. Inflate the wing in your normal way, when it is coming overhead apply as much brake as possible without it stalling back again. Apply full power and let the motor push you, don't try to run hard, as if you do this, then you will lean forward and the thrust will be vectored upwards, which isn't what you want. As the motor accelerates you, maintain your upright stance and try to keep your shoulders back, gradually release the amount of applied brake until you have enough airspeed and take off. (See the next paragraph for more detail)

Now this is the hard part for me to explain and you will undoubtably need to practice the technique to make it work well. During the take off run, you need to balance the amount of brake applied against the acceleration of the wing and your weight on the ground. What you are attempting to do here is make the wing carry as much of your weight as possible so that you are "Foot light" on the ground, but not to stop it accelerating by having too much brake applied. If you are "heavy footed" you probably aren't applying enough brake, then the wing isn't carrying enough of your weight and won't accelerate well and you risk the wing overtaking you and collapsing during the take off run.

Let's look at why this works. The attainable airspeed of the wing is proportional to the payload it is carrying. You can prove this for yourself. If you inflate the wing with only a harness attached and you not sitting in the seat, (not the motor please?) and let the wing fly by itself (you need a small slope, a light wind of a couple of miles per hour and somewhere where the wing can't flyoff or get damaged), you will discover that with a light payload of around 5kg, that the wing flies at around 5 mph (8kmh) at its trim speed. But we also know that if you are sitting in the seat then it flies at around 20 to 25mph (32 to 40kmh) trim speed. And if you carried more weight then the same wing at trim speed would fly even faster.

Now look at the speed the wing flies at say at minimum sink speed, (with approx 20 to 30cm of brake pulled) when loaded up with your weight, it's probably around 12 to 15 mph (19 to 24kmh) or maybe a little faster. So where does this get us? When we first inflate the wing and your weight and that of the motor is on the ground, the wing only wants to fly at a very slow speed (less than 5 mph), if we can get the wing to carry some of the weight then it has the potential to fly faster, remember that even at minimum sink speed it flies at over 12 mph. So by applying some brake and applying power this forces the wing to carry more payload, this in turn allows the wing to fly faster. By keeping your weight off the ground as much as possible (staying foot light) but still allowing the wing to accelerate by a controlled release of the brakes, you will find that your take off power will be optimised and you will achieve those shorter takeoff runs.

Once you are airborne slowly release the rest of the brake to acheive trim speed without flying back into the ground. Note that most paramotor / wing setups achieve their best climb rate at standard trim* and full power.

*Standard trim. Normally this is the setting where the speed trimmers are set in such a way that the risers are of identical length. Check your wings user manual to verify.

Watch this clip as an example...("Left click" to load and play in your browser or "Right click" and save as something you'll remember and can find again! Then locate the file and double click it to play.(Clip courtesy of Pierre Aubert, PAPTEAM)

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Low level flying & problems with throttle control.
When pilots start trying to fly precision turning tasks at low level the most common problem they come across is power management to maintain level flight. This particular pilot I'm speculating may have a problem other than control technique, so before I talked, all be it briefly on low level precision flying, I have illustrated some of the problems that maybe causing the scenario they describe.

"I have been trying to improve my flying skill for precision flying and low altitude flying but I found that my throttle response is not smooth or progressive enough which requires a lot of finesses and I wonder if there anything that I can do to improve it. My current problem is that I have got a very sensitive and touchy throttle response as I show in the attached picture (I did not measure the rev exactly). At idle, the engine runs between 1950 – 2100 rpm. The maximum throttle response travel, based on the cable length, is about ¾ - 1 inch. When I squeeze the throttle the first few mm of throttle travel is a bit hesitant and then the rev just picks up rapidly and I get the max rpm (around 9900 to 10,500 rpm) at only about ½ or ¾ of the max throttle response. The mid-range response seems to be rather sensitive and moves around with small throttle change. I can manage to finess the throttle response in flight to get level flight cruise (about 7,500 – 8,500 rpm). I have been trying to get a low altitude fly by but there have been several occasions that my throttle response gave me difficulties. I would very much like to get my throttle to response in the mid range more progressively and smoothly with the full throttle travel (not ½ or ¾) for the max rpm."

This is my reply...
With Reference to your problem; what you describe and the difficulties you are finding is quite common when starting to fly precisely at low level. However I’m puzzled by your description of the throttle response with regards to the full revs achieved in relation the amount of throttle applied and that it is sensitive and touchy. Normally the response is quite predictable reasonably linear in respect that max rpm is at max throttle opening. The only reason I can think of as to why your motor maybe behaving in the manner you describe is that it is running an under pitched propeller. This may account for the quite high revs for a 2004 engine and it might be that it peaks out at those revs because it is “running out of steam” as it revs beyond the powerband, although that scenario normally provides a crisp throttle response hence why I am puzzled. I suggest that you check your propeller to gearbox match.

A PAP1400 T80 with 3.6 ratio gear box should run a wood 2 blade at around 125cm diameter x 48cm pitch. A PAP1400 T80 with 3.9 ratio gear box should run a wood 2 blade around 125cm diameter and 53cm pitch.

But there are also a number of other factors that can cause slow and or erratic throttle response.

1. I think this is probably the main reason, possibly combined with under propping the engine. Depending upon the exhaust fitted to your engine the throttle response around the area you indicate on your chart can seem to be rather erratic. The reason is that some of the exhausts used on the T80 are what I would describe as “pipey”, i.e. they have a marked power band where the throttle response is crisp but if you are below the power band then the engine throttle response is sluggish. Some of the exhausts in use come onto the power band at approx 6500 to 7000 rpm and this is the region of rpm you will often find your self in if you drop the power off to avoid climbing. When the rpm drops below the power band it will be slower to respond than when it is within the power band. If your setup means you are using this band of rpm then all you can do in the short term is try to develop an ear for the engine rpm and the technique to prevent the engine dropping off the bottom of the power band.

The latest exhaust addresses this very well with good throttle response through out the rev range without a marked power band and improved response from low rpm.

2. Incorrect fuel / oil mix. Use the best fuel you can get, 98 octane (Super) if you can get it. Use quality FULLY SYNTHETIC 2 stroke PRE-MIX OIL. I use Castrol R2 2 stroke racing oil, but any other quality FULLY synthetic should do, but generally RACING quality pre-mix is likely to be better. Ensure that the ratio is right (50 to 1), use no more than 100mls oil to 5ltrs fuel or the fuel air mix will be too lean and can cause overheating and a very oily and smoky exhaust. Using good quality oil a ratio of 55 to 1 will improve throttle response and help the engine run cleanly.

3. Slow pickup from tick over can sometimes be attributed to an incorrect mixture setting on the low mixture screw. The mixture screw is the one marked “C” in the photo.

The setting on the WG8 on this engine isn’t normally critical and it will generally run quite well with it anywhere from 1 turn to 2.5 turns out. The standard setting is 1.5 turns out, so to check it, screw it all the way in (not too hard, just until resistance is felt, if you screw it in too hard then you can damage the jet seating) count the turns for future reference then screw it out 1.5 turns and try it again. If the screw is not out enough then the pickup response will be slow and the engine can sound a little like it is gasping for air. If it is too far out then it will again be slow to respond but this time the exhaust maybe quite smoky. You may need to adjust the screw “D” after doing this to obtain a tick over speed of around 2100 to 2300rpm. If the tick over is much under 2100 then often the recoil starter pawls aren’t disengaging fully and are then subject to damage. Between each adjustment let the engine tick over for a few minutes and then rev it and let it settle. Only adjust one screw at a time so that you can put it back to where it was if there is no improvement or the result is worse.

4. Your exhaust maybe broken. On some exhausts the internal baffles can break loose, if this happens then it fails to function correctly and either needs replacing or repairing. To check if it is broken, remove the exhaust and shake it to see if it rattles. If it does then it is broken inside. If that is the case then I can send you a photo to show where a workshop can cut it open to repair it. Normally though you won’t get good max engine rpm if it is broken.

The technique of flying a paramotor accurately at low level is probably the most demanding (and dangerous!) activity for both pilot and machine. With the 1400 size Top80 powered machine the pilot’s understanding of the throttle characteristics and anticipation of throttle response times is crucial for accurate flying. Smooth inputs and fine adjustments made in anticipation to power requirements will lead to accurate flying. The Top80 will never provide instant response when spinning a 125 prop, there is just too much inertia in the system, so it takes hours of practice to learn the relationship between the engine and wing. You have to learn that for a given amount of bank the wing will dive accordingly, to prevent this, an anticipatory application of throttle is applied just as the turn is input to prevent the dive. If you wait until it is diving then you have to recover with an excess amount of power, this will most often result in a climb, then you have to dump the power to get back down and hey the motor drops off the power band and is now even slower to respond so you squeeze on a load of throttle and the power comes in with a surge and up you go again! With a well setup motor and hours of practice, some pilots can get quite good at low level flying, most just never make the grade!

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