Engine Size

[paramotormike]

Hi all.

I wondered what the consensus was on engine size /thrust for the average bloke?

Here are some of my thoughts.

Smaller engine.

For .. Lighter usually, less torque, less likely to get riser twist, maybe better on fuel?

Against .. Not so good for high speed reflex wings. Climb is less. Can spend a lot of the flight at high rpm’s.

Bigger engine

For .. Get into air quicker, get out of situations quicker, can maintain level flight on reflex wings with trim out and speed bar on.

Against .. Heavier, more torque to deal with, usually uses more fuel. Newbies need to be careful with a lot of power.

Obviously there are lighter bigger motors out there, this is just a generalisation.

Any other thoughts?

Cheers

Mike

[fanman]

Beware of urban myths! It is possible to get most wings flying quickly on surprisingly small motors if you handle them properly. Conversely I've seen many people mishandle easy wings with powerful motors and run for miles! Proper handling of the wing and body position dictates launch success not outright power.

[matt_k]

Should thrust be ruffly 2/3 of the pilots weight for good allround flying?

[fanman]

60-65% of naked pilot weight is likely to put you in a very safe position assuming the harness is set as the manufacturer intended.

[alan]

I must admit when I changed my Parajet Macro to the Flymecc Carbon I was slightly concerned that it may struggle in the power department so much so I did not let the Parajet go until I had flown the Flymecc a few times.

As Fanman rightly says technique and set up play a big part and although the flymecc doesn't have the same climb rate it makes up for it in other departments cheers Alan.

[aquatix]

Proper handling of the wing and body position dictates

launch success not outright power.

True - adding excessive power to a poor technique will usually end in tears, however too little power will leave you in the 'danger zone' (ground level) for longer and need a bigger take-off area and clearance from obstacles.

A light engine benefits ground handling, so the ideal motor is always going to be a balance of power versus weight. Mine is on the extreme end of both but would be perfect if it was about 15kg lighter.

A few other advantages of a more powerful engine are that it will rev lower in level flight, so run cooler, sound quieter (with a less annoying pitch) and use less fuel. Of course this is a generalisation and there are always exceptions.

Once airborne more power can equal more fun, allowing the full speed range of the wing to be flown, faster climbs and steeper banked power turns. Having a big engine also means I could fly a smaller wing, so it gives more options.

[Farmer_Dave]

Amen to that Alan

Flew the Moster today, for the second time. Whilst powerfull enough, at a claimed 70 kg of thrust, the Simmo 200 mini2 plus, at 80 kg thrust (claimed) does seem to make light work of it. I get the impression that the fuel economy is about the same but not much happens til the Mosters really revving. Could be the 6 degree prop pitch but low passes have found me really having to nail it hard to leave the ground whereas the Simmo will climb out well at 2/3rds to 3/4s throttle.

Mosters weight would be good for a lighter or weaker chap though @ 4 kilos less than the same Simmo unit. I dont see the Moster as a replacement for the Simmo in all respects. They're both very usefull.

[aquatix]

Hi Dave, I looked closely at the Moster engine last year and your description matches what I would expect from the torque curve. A good motor but not quite enough power in reserve for my taste.

Manufacturers figures for static thrust (and dry weight) are often either optimistic or 'massaged' to give the best possible figures. More important is how it feels on your back and in flight. The Evo motor is a struggle to lift but feels fine once on your shoulders, and the claimed 30kg of extra thrust over the mini2 doesn't feel as much as I expected, but is certainly much more than anyone would need for solo. Kobra have just supplied a few Evo's for the Paraddax display team so I'm looking forward to seeing what the pro's can do with them.

http://www.paraddax.com/

One final point, most of the people I know have gone for bigger (or more powerful) engines when upgrading machines - even the lighter pilots.

[Farmer_Dave]

First time I've seen that paraddax display team. Bet they dont underfly the sparkling waterfall. Great effects and a crowd pleaser

I know a couple down here, who've changed for more power too. Having said that, I do have a great admiration for the ones that have the skill to fly with less power, and indeed, no power.

I flew my mates small 23 metre wing with his top 80 recently and I'm heavier than Deano. Must admit, I was quite surprised after being a staunch Simmo fan for 3 years

[aquatix]

The Top 80 is quite amazing for its size, and given a suitable length runway I reckon it would even get me off the ground .....

Switching between 29 and 34m reflex wings shows a difference of about 600 rpm (on my motor) for level flight. No difference in launching but the smaller wing does have a noticeably higher sink rate. A 23m would be interesting, but would make for a scary landing (steep & fast) - at least Deano had the option of dumping his ballast first.