fanman

Not really sure what point you're tryin to make. Are you saying it's too heavy to carry more than 1 hours fuel because of all the hard work you've done before?

As long as the motor runs properly with a decent prop and the wing hasn't been abused then you have done quite well. Don't be surprised if you decide you want to upgrade fairly quickly though.

Ouch, I hope that doesn't put him off. Would be great if there was an affordable 4 stroke available new.

I normally take off with around 2.5 litres for a half hour blast (I burn 2.5 to 3 L per hour) and 4 litres for a planned 1 hour flight. glad to hear you chaps aren't just gassing up to the brim regardless although I suspect there are some that do!

The motor is a bit light on power (and might test your welding skills in the exhaust area!) but it is nice and light on your back which coupled with your 80kg weight and relative youth you should find that combo fine for training. The 2002 designed Pheron is also sometimes branded as the Nova Rotor (unfortunate choice of name bearing in mind what we do) and I think there were a few people paramotoring on Rotors recently who said it was quite good under power for a PG wing. Bearing in mind the low power power output of the Racket engine it's probably wise to be on a non-reflex wing like the Pheron. The 2 days PG training a few years back won't be totally lost as you have some idea of what lies ahead with regard to wing handling. How much did you pay for your kit?

Just out of curiosity, what set up have you bought, what weight and age are you and do you have any previous paragliding experience? Becomes a lot easier to help when you have some basic facts.

It would also be interesting to know how many litres of fuel people take off with to do these average flights.

Recommended weight for the 26 sq m small size is 70-140kg so in terms of weight you are fine at 125kg all up. If you are a complete beginner it is then just a question of whether it is the right wing to start on. I don't know enough about the HP version to comment on this.

2 strokes work best in their powerband. You have now started operating you machine out of that area and are in the very vague mid-range. you can't use the top end because of supersonic efficiency losses so i have to wonder what you have gained! It must be like permanently trying to drive a Ferrari around in 1st gear.

Need to be very careful with that site Kev as some of the data is wrong.

Been doing a fair bit of looking around and everything to do with the MZ34 points to Paratoys/Black Hawk and noone else other than the engine manufacturer, Compact Radial Engines in Canada. BH seem to prefer smaller diameter props so bearing in mind you want to put the lump into a larger frame then I think it's worth a call to helix for some serious advice. They tend to work in pitch angle rather than pitch distance and then measure it at 5cm from the tip rather than the standard 75% span so take the advice but don't try to apply their numbers to other manufacturers props as it doesn't work (generally need to add 3 degrees to get a comparison to other manufacturers props which I suspect is due to a different way of measuring). Helix are the Rolls Royce of paramotor props (closely followed by Pulse), they aren't cheap but you are obviously looking for efficiently converting large amounts of horsepower into large amounts of thrust. A cheapo prop on a big engine could easily deliver less thrust than a good prop on a small engine.

I'll look into it and get back to you.

It's actually higher than most paramotors. Most run between M0.4 to M0.5 unlike light aircraft that often do M0.9.

Assuming your motor has belt drive rather than gearbox it would sound like you are after a similar (but reversed direction) to a Ros125. Therefore a Helix prop for your machine would be model H30F 1.25m L-M-08-2 with a 6 hole 75mm PCD. You may need new prop bolts to suit the hub thickness but these are easily obtained locally. If it's a wooden prop you are after then I would look into contacting Aerobat in Spain with the dimension you stated earlier. They make excellent props.

Most manufacturers use other companies to make their props for them. Presumably it is the Walkerjet you are looking for a prop for so we need to either find out who made their props or what props other similar Walkerjet units are using successfully.

One of the biggest mistakes inexperienced people make in this sport is prop choice. It is possible to get a cheap prop but you must REALLY need to know what you are doing. Buy cheap, buy twice (second prop will be the one you should have bought in the first place so you will end up spending more!). Manufacturers put a lot of effort into matching props to motors for good reason. If you don't know what you are doing then stick with the manufacturer.

How many hours has your motor done and what are the details of your prop (manufacturer, diameter and pitch)? As mentioned earlier in this thread a lot of dealers send out the machines with props that are right at the top end of what the motor can sustain which allows it to keep its reputation for being a powerful motor however a few hours into its life and it struggles to be able to continue swinging this pitch so after a few minutes of running it gets bogged down. But "hey, it's still the original prop" so it can't be that that's wrong, so then starts the process of rebuilding the carburettor, the ignition system, the redrive, the crankcase seals, etc, etc until someone who has been there before tells you that you've just lost the last seasons flying chasing an apparantly unresolvable problem because of something you swore couldn't possibly be wrong because it is original! When this motor is on song it is a really good motor. The trouble is it takes a bit of understanding and pooling of knowledge to keep it there.

They do but its very very expensive and not much like a paramotor to fly. Stick the FB unit on a generic trike unit. The Paratoys LowBoy quad is actually very good and far more stable than others. I believe it can take an extra seat on the front but I've only ever been on one solo.

How did I forget the SportiX, it's the best one in the range.

Terry, thanks for taking the time to write all that, it really helps with diagnosis. You're right, you shouldn't have taken it up to full revs with no prop on it! With no forced air cooling system (fan and shroud) the BD is totally dependent on the air drawn by the prop for cooling. It also needs the prop for its flywheel effect (especially important for the pull start version). The BD was originally designed to run at much higher than its current max 7500rpm so hopefully everything should be fine. There are some guys that deliberately run fine pitch to obtain over 8000rpm regularly. The best way to get the right belt tension is to warm the engine (and belt) up by running it. Then switch off and put a torque wrench (preferably the old type with the bar indicator) on the nut that holds the small pulley on and turn the prop by hand. if the tension is correct the warm belt will slip at somewhere between 15-18 foot lbs. More than this and the belt is too tight which will damage the bearings, less than this and the belt will 'chirrup', slip and wear quickly. The annoying thing about this pitch issue is that it will send you looking at every other component of your machine before realising that it was the prop all along. Ask DanTheMan, he went through exactly the same issues with his HE R120 last winter until we convinced him it was prop related (his prop was 6 inches overpitched!). My personal recommendation would be to bite the bullet and go to Fly Products and get another original Kompress prop or failing that go to a guy called Mike Hay in the States who knows BD props inside out (he makes beautiful wooden ones) or GSC for either their fixed pitch or ground adjustable. Avoid the Woodcomp sold by the UK BD agents as you will have the same problem you are having now. PK is a nice guy but almost every problem prop I have come accross has originated from this source.

Pete's absolutely right, the FB is the better of those 2 makes by far. If you wanted to just fly by yourself then the Solo powered one would be fine for your weight but if you really intend to do tandem then you should be looking at the Simonini (preferably with the comfort bar setup).

Terry, I am now trying to pick info out of your last post. Are you saying you now having problems since running a replacement prop supplied by Paul Kilburn having destroyed your original prop? As requested earlier, please give us info as to the make and model of props giving the original performance and now the make and model of prop that you are having trouble with. Just to give you a heads up, I am currently helping someone else resolve prop issues who was originally running a Helix but then broke it and replaced it with one from the same source you mention. He is showing the same problems (different motor though) so we removed the replacement prop and carefully measured it. The stats we found were not consistent with any prop manufactured for aviation use so bearing in mind the factory in Thailand that 'copies' props for dispatch to the UK are actually furniture manufacturers we are wondering if it was copied from an ornamental prop designed purely for hanging on a wall with a clock mounted in the center! Many people try to cut costs when replacing props but it is too much of an important part to do this. You wouldn't drive your car at full pelt down the motorway in 3rd gear but this is often what people are doing when trying to fly with the wrong pitch prop.

It's not just about the motor, there are so many other variables that you can't really quantify weights to engine size in such a simplified form. There are some big motors out there connected to rubbish drive systems that struggle to get light pilots off the ground and can exhibit unsafe levels of torque and propensity to riser twist while other big guys can fly well on surprisingly small motors if proper attention is paid to matching the kit and setting it up right.

Reckon the belt change just looks worse because the ring gear is unusually on the prop side of the redrive belt. Probably just take the starter motor off, release the belt tension on the eccentric cam and slip it completely over the ring gear. I reckon with the comfort bar attachments rather than J bars that looks like a superb machine for the wider than average load. Prefer the other type of throttle FB occasionally do over that Airboss throttle thingy. I find you catch the kill switch to easily on a forward with the airboss throttle system.

Terry, these guys above are just speculating... go to the Black Devil group and find yourself surrounded by many people who have had exactly the same problem. The Black Devil is renowned for suffering a power loss at around the 50 hour mark and then becomes unable to retain the power to swing the prop it was originally supplied with. This problem is further exacerbated by one current dealer in the UK and one former large scale supplier in the US who constantly recommended props that are now widely understood to be overpitched for this exceedingly pitch sensitive motor. Ask yourself why so many of these motors are flown with ground adjustable propellers. The problem is usually even worse when people break a prop and then try to source aftermarket ones. Did your prop strike require any repairs to be made to the prop? Can you tell us the manufacturer, diameter and pitch of the prop as well please.