With the new AMA Park Fly Program where the limit is 2 lbs and 60 mph how is the speed verified? Winged Shadow Systems www.wingedshadow.com has a neat little device, the HOW FAST ($44.95) that does the job. The 2.7 gram unit, plugs into your receiver and includes Pitot and static probes that mount on the wing. Maybe a good item for clubs to consider.

Here's another alternative for clubs that want to check on things like this. It also gives them the opportunity to check any plane flying and it doesn't require anything to be attached to the plane.

[link]http://www.walmart.com/catalog/product.do?product_id=4661205[/link]

This is a radar gun sold by Hot Wheels. It can be found at most Wal-marts for around $30.

Ken

So, folks join the PPP to save the difference between $58 and $29, then the clubs require them to buy a $45 device to prove they are in compliance with the $29 program.

Classic!

P-51B

What you didn't consider is the cost should be attributed to the model cost. Since these electric flyers are underprivileged and as result usually save so much on the models they should have no problem affording such devices for their airplanes. Heck, my last park flying model only cost $525 to build and equip. I decided to stay with the full AMA for now though and will not have to worry with proving my airspeed to the field Nazi.


BTW there is some good Doppler sound wave software that also can be used to determine model speeds. It is possible to video a suspected offender and then analyze the video latter. The field Nazi would then have recorded proof of the violator so that he can be properly indicted and reprimanded in club court.

60 mph is 88 feet per second. ([60 miles per hour X 5280 feet per mile] / [60 minutes per hour X 60 seconds per minute] = 5280/60 = 88 fps)
Simply mark off a 264 foot-long pair of markers on your runway and fly the airplane past them. If it takes more than 3.0 seconds to fly the distance, the plane is flying slower than 60 mph.

Is that before or after the dive from 400 feet?

How do we diferentiate between
"Fly as fast as you can from pole1 to pole2 for the judges to stopwatch"

being used for PPP verification,
vs being used as a contest of speed , aka RACING!
<that may require AMA set spectator safety distances & hardhats for all within certin danger distance>

Perhaps we can all avoid the racing safety when 'informal racing' by just calling it a PPP velocity qualifier... uh, PPP velocity qualifier with 1st - 3rd place awards. Lets run this by the folks in the PYLON forum and see if they think we can just willy-nilly stopwatch planes from Pole1 to Pole2 without nobody wearin hardhats and not use set safety distances to people. Sure the safety rules for such activity are not prohibitive, but they need to be read & used.

It is just one way for the PPP guys to race
<"The 5 of us will each 'PPP-Qualify', the lowest time 'clostest to failing' gets to wear the speed badge till the next race 'qualifier'. " >
without abiding any race safety on hard hat use.


Otherwise, laying out ~300' of runway in the new Legendary Urban PPP Field might be a tight fit for the guys that are the ones that will actually have to do this: The (urban) PPP Clubs that fly FFF3d in a 100'x200' lot behind the supermarket.


Maybe we can use the Pitch Speed method,
and just ignore the way overpropped planes (overpropped batteries) can gain 30-50% RPM once upto speed.

I like the Paintball method,
Have a paintball marker chrony'ed to 88 and shoot the plane from behind.
If it outruns the ball it is a Violator.


However, since we were all were just reading how Muncie told a guy the club would be ok if they didnt police the PPP, why bother making the club buy a Radar or PitotPressure device when they can just ... do nothing.[sm=thumbs_up.gif]


How do we tell if the PPP is under 60 or not.
I think that is a great question. Of course I am biased on that, since I asked that question in a couple of threads months ago.

Doesn't seem to be a problem gauging 100 mph for night flyers or 400' in altitude for the $58 guys. Besides you should only need to take the trial 1 time on your machine, the requirement is for 60 mph in capability, not overall top speed. Once again we are debating a simple solution and process which is blown out of technical proportion. It really isn't that difficult to find out, even for us PPP's.

The bottom line here is... YOU DON'T (verify PP plane speed, that is)!

You're better off from a legal standpoint not having a way to measure speed, just like you're better off not having that "BEWARE OF DOG" sign on your door. By having a radar gun, you're admitting that the plane can go too fast, just like in having the BEWARE OF DOG sign, you're admitting that your dog is likely to attack someone. Either one makes proving negligence a slam-dunk for the plaintiff's lawyer.

During a period of fiscal disadvantage, I lived in rented cottage on the wrong side of the tracks. The sign on my door was "THERE IS NOTHING INSIDE WORTH A SHOTGUN BLAST IN THE FACE." Was I placing myself in peril re the lawyers?

Abel

Actually I know all this speculation is just space filling tongue-in-cheek BS because there is no way to accurately measure the requirement as stated.

Red knows that any pitot-static system displays Indicated Airspeed (IAS), which must be corrected for pitot installation error and compressibility to obtain Calibrated Airspeed (CAS) which must be corrected for air-mass-density (temperature and pressure altitude) to obtain True Air Speed (TAS). To obtain ground-speed (GS) the actual wind vector component must be applied to the True Heading of the aircraft to obtain actual Groundspeed (and drift angle).

Now let us examine the AMA ruling from their website: http://www.modelaircraft.org/parkflyer.aspx

>>>Park Flyer Definition:
Park Flyer models will weigh two pounds or less and be incapable of reaching speeds greater than 60 mph. They must be electric or rubber powered, or of any similar quiet means of propulsion. Models should be remotely controlled or flown with a control line, remain within the pilot’s line of sight at all times, and always be flown safely by the operator.<<<

OK! That says INCAPABLE of speeds greater than 60 mph.

In all known aviation terms the model cannot attain a speed of greater than 60 mph of TRUE AIRSPEED. Therefore all the above methods in this thread are rendered impotent.

Now notice the limitation does not specify whether the model is going straight and level or straight down.

Now should the rule apply to "Straight Down", then how are we to know each factor in any specific model's bouyancy, drag and acceleration time to terminal velocity?

Again AMA leaves us stranded in free fall because they do not define their terms. Whichever direction and situation one might select, then he could be proven in error because all other factors were denied in that specific selection.

The only actual selection really available as far as what the model can reach is the Indated Airspeed figure, since that determines the drag on the machine which will determine the ultimate capability. That will change in actual velocity, TAS, due to air mass density.

So all this rhetoric about how to determine speed is just that -- rhetoric -- same as AMA rules made by those that know not and know not that they know not. Bad spot to be in. BTDT

Interseting that hoss brings up the Straight Down factor.

While the AMA has made passing reference to level flight for the 60mph cap,
in most cases where someone or something was hit by a RC plane,
the plane was either going in some degree of downward vector or just concluded a downward vector,
cause folks & things aint up in the air, we are on the ground and any plane that hits us has to be going from up in the air to down on the ground.

Will all colissions be at StraightDown?
Heck no.
Will the majority of collisions be in some degree of downward travel?
Obviously.

In measuring "incapable" does that mean terminal velocity under power, or wing shear?
Just asking because, like Hoss alluded to, Incapable has a very distinct meaning, and planes that can only go 60mph sustained level are very well capable of grossly exceeding that in even just a 45 dive.

But I've also seen GWS Tigermoths land with a negetive goundspeed in controlled foward flight.

We are dealing with the technologies of batteries; planes that go 55mph on a 3s 11.1v battery might go 70 on a 3s 11.1v battery <of higher C or mAH>. Voltage load drop is a fickle mistress, changing out the 3cell for another 3cell can require retesting.... which means will we have clubs retesting every flight, or having to hold the guys hand as he changes bateries to make sure the exact same componants are used every time?

But sometimes it is just obvious the plane dont exceed 60mph, thus is safe, like this [link=http://www.zagi.com/media/ZagiFixxWebClip1.wmv]PF manufacturer video[/link] <check the 25second mark [X(][:@]>

Yup. If somebody busted through the door and you blasted 'em, they or their family could sue you into oblivion for wrongful death and you wouldn't have a leg to stand on. Without the sign you could claim self defense. With the sign, it's premeditated murder.

Ok, this thread is spiraling out of control quickly. Let's get it back on the topic that Red asked about.

Thanks

Ken

not interested in verifying any plane's speed. that is the local safety nazi's job. and, if i happen to notice him trying, i will do all i can to screw with his measurements.

I feel this thread's really about liability, not airplane speed. We'll all be much better off simply not knowing how fast the planes are going, and not being able to measure. Do we really want to open that can of worms? Besides, the wording is indeed INCAPABLE. Nothing is mentioned about measuring the speed of the plane.

But since we know all planes are capable of well over 60mph,
given a dedicated enough modeler and an adequate supply of G rocket motors,
or even simply putting a 300w brushless 7x6 on a SlowStick/FFF,
we do need to be able to see if the plane that came from the factory with a 'PPP OK' sticker is still going under 60mph when they swap out the stock 50w for a 300w.

Before the CandyStripers put insane motors in their mopars, the street legal cars didnt lift the front wheels up in the air when you put the hammer down. Before the 3d Parkies put 300w brushless in their GWS Warbirds, the planes didnt hover... and swapping the prop to a cut 6x8 will have the slowfliers approach mach

Sure the box has a PPP OK sticker, but the factory motor is still in that box with the sticker.
The question is not whether that plane was OK from the factory,
the question is whether that plane is ok as it is currently setup.

Muncie may say the clubs dont have to worry enforcing the rules, but we all know they do.
Otherwise we can just eliminate the position of Safety Officer from all clubs, since we will be having selective enforcement of some rules but not others.

The planes DO need to be weighed, and they DO need to have speed limits ( Incapabilities ) verified.
This thread has brought up a few good (& otherwise) methods so far.

Pitot System measures airspeed not groundspeed.
WallyRadar seems good so far.
Pylon Timing doesnt work in 15mph wind, when a Tigermoth can have negative groundspeed in foward flight.
Doppler Analysis has potential for AMA web use, but also has abuse potential.
But for fun we'll all be getting Paintball guns & thumping the 88fps "PPP Balls Of Safety"


<edit: Corection -
A member of my crack staff of fact checkers just gave me a correction to make,
Or, more accurately, a guy on the boards saw me swing & miss,
The CandyStripers ran in a stock class.
<->
I guess it was Mopar themselves that felt the Hemi needed to be in those cars. Works for me[sm=thumbup.gif]
Perhaps I should have stuck with the V8 Vega example I used elsewhere.

Then, without the 15 mph headwind, the Tigermoth can't go any faster than 15 mph. Problem solved.

Seriously, one just needs to measure the time between pylons going both directions, then average the two to remove the effects of wind.

OK Matt, I'll buy that. Modelers like challenges; somebody claims a GWS Tiger Moth can't reach 20 mph, and you can bet the farm somebody will be back tomorrow with a shot of a radar gun screen showing that one he equipped with a 50 mm outrunner and 8 cell Lipo pack was clocked at 120 mph, and never mind that it shed the wings during the speed dash.
Let the insurance co. lawyers trying to beat a claim show the model that crashed into the school bus was capable of transonic speed. I had no idea it could go that fast, and the ambulance chasers have no way of proving I thought otherwise. Works for me.

Abel

Maybe I dont have to worry about the increase wt going from Geared300can to Brushles300w making it over 2lb,
if I dont have to worry about the 300w getting it over 60mph.

If that is the case, then I can spend the extra $11 and get the 400watt setup for just 2oz more (+3oz more batt).

If we are not going to care about the speed limit, who is gonna care about the weight limit.
.... now where did I put that MetalProp for it , that bad boy has a date with the whetstone to get it nice and sharp I mean efficient

Although granted that is close enough for toy airplanes, that method does not "remove" wind effect.

Here is the question: A plane flies at 100 mph TRUE Air Speed. The distance between A and B is 100 miles. The plane will go from A ....to ....B, sharp turn around (disregard turn time) and back to A. There is a 20 mph steady wind blowing from B to A.

Plane flies the 200 miles at a True Air Speed of 100 mph with the 20 mph wind from B to A. The total time required for the trip is:

A. 2 Hours

B. Greater than 2 hours

C. Less than 2 hours.

D. None of the above.

While this sounds "off-topic" it really isn't. If one wishes to discuss airplane speed, then one should understand the subject.

Oh goodness, Hoss!

Maybe the AMA just needs to create it's own version of FAR 25.333 so we have to create V-n diagrams and flight envelopes for our toys. Throw in 25.1505 for Vmo/Mmo and we'd be all set!

I think the best way to find 60 mph is to use what's known as a "judgement call". Afterall the AMA allows us to be insured using the judgement call which states we should fly in a safe manner. In a safe manner compared to what? I've seen guys that couldn't willingly or unwillingly fly in a safe manner no matter how hard they tried. In fact about half of the AMA safety code is based on use of good judgement. I also think it was rather liberal of the AMA to confirm that shooting projectiles ground to air at RC aircraft while doing so in a safe manner, is flying an aircraft in a safe manner. Again, a judgement call.

Besides when was the last time we saw someone come into the AMA forums or any other forum and announce that the AMA would not pay their benefits? Well in all honesty ... I can't remember one time.

So go ahead and whip out your E6B's, radar guns, stop watches and VASCAR devices. Me, I'll use common sense and 2nd grade math.

400' only applies within 3 miles of an airport, 60 mph will apply everywhere.

Saying the best way to find 60 mph is to guess seems like telling someone you owe $1000.00 to that the small stack of ones you gave them looks about right, no need to count it...