这是一篇老飞行员的经验之谈，考考你的英语水平，大意是说买伞时，千万不要听生产商、经销商鼓吹他们的产品，要多听朋友建议介绍，买机器时要考虑配件的供应、维修及启动方式等等，选伞时要根据自己的体重。动力伞用的伞头与普通滑翔伞不太一样，自己不要随便组装。
What you need to know before you buy a motor.
If you don't have time to read this page on line. Just print it and read it later or better yet save it on your drive. I guarantee it will save you a lot of hassles & headaches & money too. Everything on this page is from my personal experience & talking to many pilots & my best budy Lucky, the two-stroke engine doctor. I share it with you because I want you to avoid the pitfalls of buying a motor. If you disagree with anything which I write here, just email me your opinion & I promise I'll post it right here & give you the credit for it. It can't be more fair than that!
when you are ready to buy a motor, know that there are many, many brands and models of motors available to you.
Don't' listen to what the dealers say about their motors or other brands of motors. Ask the following questions:
Can you send me a price list for replacement parts for your motor.
How long is the warranty & what does it cover? Can you mail me the written information.
Does your dealership have mechanic to do the repair work. Some of these engines require very special tools to work on them & not every mechanic has them or can get them. What is the hourly charge. Who pays for the shipping & handling while under warranty.
Does the motor come with a tool kit? Is the owner manual updated. It could be the owner manual for the motor which they first came out with.
How much the wet motor weighs with all options. That means electric starter, Gas, harness ready to fly. If it weighs over 60 lb don't buy it if you are going to foot launch.
What kind of RPM? Motors which have a high RPM wear out too soon & are noisy. 7000 RPM should be max.
What kind of static thrust? if less than 100 lb & you weigh more than 180 it is not a good match.
What should be the HP of the motor? It should be any where from 17 to 26. Too much power creates too much torque. Too little power well, you can't get out of bad situation fast enough.
What about the diameter of the prop? Too small of a prop will not give the thrust you need, since your body & harness is blocking most of the prop. So the prop should be more than 36 inches. Unless you are very small person.
If the prop is too large i.e. 50 inches or more then your prop guard is too big to clear the risers in forward launch. You have to be a very good pilot to use that big of a motor.
Does the motor have electric start? I would not buy one without it this is my personal preference! On landing you should always kill the motor and land as if you were paragliding. This way if you fall you don't break the prop or get your lines caught in the prop. Many times pilots fall on one side and bend the prop guard. The turning prop hits the bent part & breaks. Some times you may have to restart your motor to try your landing again. If you find thermals you can kill your motor & thermal for a while. Also if you fly to a ridge & it is soar able, then you want to kill the motor & save your gas for the trip back.
When the motor is cold will it start without the choke? After all while ridge soaring or thermalling your motor is getting cold. How the heck are you going to use the choke to re-start the motor in the air.
Does the motor have internal decompression. That is an old design which basically a flap in front of a small hole allows the compression to be less at startup. But the carbon built up will make this obsolete after a few hours of use. You have to take the motor apart to clean the valve. I would not buy a motor with that kind of decompression valve.
Does the motor have external decomp valve? Motors like DK Whisper & Whisper Plus have that. It works great with electric start. But you do need to take them off once in a great while and clean them. It is very easy to do it. I would buy a motor with that kind of decompression valve. Just make sure if the motor has electric starter, it automatically press down the decomp valve for you. While up there in the air with the motor on your back there is no way to press the decopm valve down to restart the motor! So it has to have the mechanism to do it automatically.
Some motors are without decompression valve all together. They are the best. Of course the recoil starter has to be a little bigger so you can hand pull start it. Also the electric starter has to be stronger to roll the motor over. But then you don't have to mess around with the problems associated with decomp valves. Remember they can leak the precious pressure too without you knowing it.
What kind of harness does the motor come with. DK harness are very nice. But they don't allow you to do too much weight shifting. Then again you have to remember if you are flying with motor you are not that much into using those skills any way.
Make sure the hang points are on the harness & not on the motor frame. On some old design the hang points are on the frame of the motor. If due to fatigue the metal frame breaks you will separate from your motor & fall! The new design if something goes wrong the motor will fall & you stay with the wing.
How many cylinders should your motor have? One cylinder will do. Two & three are just smoother. But there are more parts to break & replace. There is a little bit of safety factor in two or three cylinders. If one spark plug quits working the other one will work till you get out of a bad situation.
What kind of prop? Composite props are better than wood. But more expensive if you break them. Find out how much is the prop. Make sure the price is for the whole prop & not for one blade!!!
If you are planing to go to 10.000 feet above see level, you need a big tandem motor. Don't believe what they tell you about the ceiling of the motor. That just means that the motor can operate at that altitude. It won't climb there. And if it did, it will run out of gas by then!
Most paramotor use the Solo 210 as their engine. When comparing prices make sure you know what kind of carburetor & exhaust system you are getting. Tuned exhaust are very useful. Do ask for them. Carburetors with float don't ask for them!
Aluminum frame is just as good as stainless steel. If you crash both of them will bend & break. Make sure the frame is not one piece. It cost more to replace it. After all if you bend the prop guard, you should be able to change just the prop guard. Some of these motors are built like cars which after an accident you have to replace the whole side of the car because of a dent.
Number of props? The more blades the slower the prop has to turn to generate the same thrust. So it will be quitter. But then you will have more weight & expense when you need to replace it.
Direct drive or reduction gear. Well from what I have gathered two cycle engines have to turn at a high RPM to make it useable. So direct drive does not make sense. One belt or two belt does not make a difference. I am told at high RPM if one belt breaks it will kick off the other one??
Fuel tank above the motor or below the motor? Personally I like the fuel tank to be below the motor & muffler above like DK GT. After all if you get a leak in the gas tank you don't want it to drip on the hot motor.
Price of the motor? You get what you pay for does not always apply here. You get what you did your home work for. So take your time. Try to check out as many motors as possible. Read the " Motor Rant & Rave" Page on this site. Email some of the people who have had problems. Find out how the dealer treated them. How much it cost them....
Remember if you buy a motor which the engine is build by the motor manufacturer, you are at their mercy when you need the parts. For example; you can buy Solo parts from many dealers. DK parts are sold by DK dealers only. Another important issue; some engine cylinders are designed to be repaired if scratched or scored. Some are not. So it is very important to know that. Most motor cycle shops can repair your cylinder. But if this is what your dealer says about your engine "The crack can not be welded. You need a new crankcase. The cylinders are chrome-plated and can not be honed, or polished, only hand-washed and dried. You need a new cylinder". Then you are in it knee deep! For a cylinder to be repairable by any shop, it needs to have a removable head. One piece cylinders are not repairable.
Finally what kind of wing? Well if you already have a wing and you are not going to be too heavy with your motor, then use it. If you are new to the sport buy a wing which is easy to launch. After all with all that weight on your back who wants to fail a launch and try & try again!
As I come up with more points I will add them here. If you have any, please email them to me.
I realize that one motor can't do all the above and be inexpensive too. But if the pilots are informed then they will pay more to get what they know they need. No one is crazy to buy a cheap motor & fly it knowing that it will quit on them in the air. Or when it comes to the repair job, they are better off buying another motor rather than fixing the one they have.
So this page is to inform those who are thinking of buying a motor. Knowledge is power. Exercise it. There are many good motors out there with good people backing them up. Don't buy a motor for its look. Buy it for its performance. As soon as you are 200 feet off the ground all the motors look a like! It is just a fan on your back! But they sure don't act a like. A super tuned exhaust is as ugly as it can be. But it makes your motor perform at its best. It makes it sound quieter. It allows it to have a longer life....
It would be great if a motor could be built to be a beauty without sacrificing the performance. But till that can be done, go with a motor which covers most of the above criteria!
Thank you Ray Kashefi |
