Microlighters

Hi all.

I fitted a nose fairing to my trike, to try out in this "lekker" cold weather of us. But it seems that my takeoff run has increased and my climb rate decreased. Apart from the weight added to the nose ( and I must say, it's not much ), I thought about the effect the wind or air supply might have on the prop. I attached 2 drawings to try and explain what I mean. The drawings is not on scale. The one shows "normal" airflow to the prop, and the other shows what I think might happen to the airflow as it passes over the nose cone. As you can see, I think there might be a big portion of airflow "diverted" away from the prop, and you might loose efectiveness on the red parts as indicated.

Solution : 1. Take it off and face the wind
2. I currently have a 70 inch prop, upgrade to a 72 inch or even more ?

What do you all feel ....

Drawings

be careful,

a fairing acts like a wing but to the side. On a 3 axis aircraft you have a rudder to stabalise the aircraft. One of my planes, the Challenger, would exhibit strange behaviour when you just install the doors, requiring some serious rudder work to keep her stable. Installing a fairing is much more significant and the fairing is going to steer the plane perhaps where you don't want it to go.

Have a test pilot fly it. I anticipate you having problems on landing, it's not going to handle the same way. a side wind is going to push the plane left or right

Jaco, take a pic of the trike with fairing and post it here please

Pic

What you say is true Morph. Thanx for the reply. I have'nt flown it in any wind yet, only take her out when it's dead calm, will get to that later. Landing feels a bit different, but no problem. I'ts only the longer takeoff run that has me a bit worried. When I fly solo, it doesn't really bother me, it's when I have a pax, the runnway gets short, quickly. Do you think it can have a effect on the prop ? as shown above ? would a 72 inch prop help ?

Thanx all ....

I did most of my hours on a windlass 503 & Aquilla 582 without a fairing (sp). 2 months ago I was certified on a 582 trike with the fairing and found it a handfull on take off & landing. Besides sitting far closer to the ground in the viper I felt the aircraft would "float" on takeoff & landing and only nailed it on my landing last Sunday afternoon. The only explanation I can think of there is some sort of cannard effect at work generally when in ground effect I was not particularily impressed with the aircraft before I figured it out. There may also be less/more of the "wind in your face" which tells a microlighter a lot & I am sure this is something we unconciously take note of & react to. Its a bitch to get out the hanger unless someone is inside & can steer for me, and I'm still not happy about having the whole front end enclosed where I can't check it all out in preflight. ( Caution with the shoe size as well, it gets cramped down there. I am sure a size 10+ is going to battle.)
I also found its easy to leave stuff on the floor of the fairing (found my glove there & some cable ties).
It took a while to get used to, I'm happier about flying the aircraft now but still have not made my mind up which I prefer.

Hi Jaco,

Your pic on air flow is not quite right. The prop tends to create a vacuum which in turn is dragging the air from the side and front into the prop. Ask Gert Coetzee about the defference. He has 2 trikes, one with and the other without a fairing. Each trike has got different flying caracteristics, so you must just go out and test the aircraft. If the runway get short too quickly, maybe you should think of changing your wing setting for a bit more lift.

JACO wrote:Do you think it can have a effect on the prop ? as shown above ? would a 72 inch prop help
Thanx all ....

The fairing is quite low down, I can't see it creating too much of an issue for the prop. Obviously one of 3 things has happened;
1. either the thrust of the prop has been affected, although It can't be by much
2. YOu have added weight to the plane
3. You have increased the drag,

I would say probably 2 and 3

Jaco
Looking at your images,
I work with a couple of engineers and even a guy that designs the blades for gyro-copters. The line of your fairing to the seats may cause more drag than you think. Remember that wind can get in anywhere, and it "whirls" in form the edges of the fairing back to your legs. It then only gets less with a faster speed, if you understand what I mean. You will not take away air-flow from the prop that way,but, you need to look at the bottom air-flow-line of the fairing as well.
Please send more info about how you progress with testing the fairing...there is a couple of guys flying with and without it that would like to know other pilots preferences on adding fairings to olders trikes.

regards
Conrad

Hi Jaco
Enige nuwe verwikkelinge op die fairing?
Het jy dalk meer images waarna ek kan kyk asseblief.
wat is jou engin grootte en hoe ervaar jy die wind tans?

groete
Conrad

Another thing, put the tricycle into a flying attitude, Normally nose up. Then look at the allignment of the fairing. You might find it's pointing up or down, adding to the drag

Morph wrote:Another thing, put the tricycle into a flying attitude, Normally nose up. Then look at the allignment of the fairing. You might find it's pointing up or down, adding to the drag

Good point. If I look at the pic, it would seem the cone would face upwards as opposed to level when the trike is in flight.

Jaco, I do not believe that the blue cone can have any effect on your take-off run. The very high angled perspex screen however will definitely tend to push your nose down into the ground as you accelerate on take-off.
See if you can remove the screen and try it again.

Once in flight, you will find that Morph also has a point with the blue cone adding drag rather than reducing it. Keep us posted.

Hi All

Ok, I took the trike, nose fairing and all, to my instructor, over the weekend, and he we did some ground tests & a couple of flights, one up, with pax, low fuel, high fuel, ext.

Using a tape measure, cones, short takeoff maneuvers ( bar pushed against profile tube ), we came to the conclusion that I was way wrong.

The takeoff distance improved ( shorter ) solo or with pax, the climb rate was better, in all the weekend’s testing it seemed that the fuel consump was also better. Landing was a bit more difficult ( for me ) because some of the view I was accustomed to disappeared. No crosswind landings yet.

I also think the screen is way to high, don’t know what the average is, and I also think the cone is leaning backwards, This I will try and fix.

Thanx All, will keep you posted ....