mini scout max speed

Kaona

Member
I have a setup that will run this plane at 109mph with 100% end point on the throttle.
Can I set my throttle endpoint to 65% so it will only do 80 miles an hour at max stick input?
 

Ketchup

4s mini mustang
Will this plane even handle those speeds?
What is the max speed for this plane?
I don’t think that this plane would handle that. I haven’t built one, but I know that you will need to strengthen the wing a lot. Also, it isn’t made for speed, so it would have a good amount of drag at those speeds.
 

Ketchup

4s mini mustang
I have a setup that will run this plane at 109mph with 100% end point on the throttle.
Can I set my throttle endpoint to 65% so it will only do 80 miles an hour at max stick input?
I don’t know if it will do exactly 80 mph at 65% throttle, but it will definitely go slower. Also, have you flown rc planes before?
 

Kaona

Member
Motor, prop, ESC, battery, AUW, pitch speed, wing area.

Do you want me to post the calculations?

They're not necessarily for this plane but a similar plane with this setup and specs.
 

JasonK

Participation Award Recipient
Air resistance can be calculated by taking air density times the drag coefficient times area all over two, and then multiply by velocity squared. Where are you calculating your air drag? because 2x speed is 4x drag. Also, prop thrust goes down as the plane speed goes up.

if you have a calcualtion enought to tell you your 'max speed', just plug in your 65% throttle values into that same equation and see what speed its say your plan is going to be going. for that matter, you should be able to plot a full curve of throttle to speed with the equations.
 

JasonK

Participation Award Recipient
then just throw in the various throttle values into your equation and you should get a speed by throttle curve.

without seeing how your doing it all (IE the actual math), no one call tell you if your close or not.
 

Kaona

Member
Dalprop Q4040. This is a 4 blade prop.
Calcs are even higher with other props.

Screenshot_20200424-101026~2.png
Screenshot_20200424-101045~2.png
 

Kaona

Member
I have used this calculator for quite a while on quads and it has been on the money every time. I build them to sell and it prevents me from buying components that won't work together.

Never used it for setting up a plane.
 

Kaona

Member
I noticed on the other setup that the wing loading was excessive according to the model specs but with this setup posted below the wing loading is just under the specs. The basic difference is a 2305 2800 edge motor with a 3s 450mah lipo instead of a 2306 2700 and 850 battery.

Seems a bit more manageable and doable. And if I wanted to rip the wings off it just put a 4S battery in it.
 

Hai-Lee

Old and Bold RC PILOT
There are relevant factors not included in the Calculator that you are using that would seriously effect the actual maximum speed. The most serious omission is the coefficient of drag for the airframe itself.
As the drag coefficient can vary considerably subject to the aircraft design so will the actual maximum speed. As an example to consider would be a biplane and a WWII monoplane fighter design. Both could weigh the same and even have the same wing loading but the speed difference with the same power plant would be considerable.
I also build and sell RC models though I do so with fixed wing models only! If you are needing to evaluate a single motor across a wide variety of different aircraft models, (bulk purchases for best pricing can reduce the variety of inventory for a small manufacturer), you can vary the prop specifications as well as the battery size and cell count to give the required performance figures.

In your original post you were searching for ways to easily reduce the maximum speed of the model. The simplest method is to underprop the motor so that at maximum throttle the prop generates the required maximum thrust JUST!
If you are selling the setup under you require the end user to miscalibrate the throttle for correct operation I can assure you that the proper calibration will almost never occur and you could be facing a reputation destroying product and possibly a large number of warranty complaints or claims.

Just my opinions of course!

Have fun!
 

Kaona

Member
I don’t know if it will do exactly 80 mph at 65% throttle, but it will definitely go slower. Also, have you flown rc planes before?


Yes, I have flown rc planes but they were all nitro builds. Once I started with quads I gave all but 2 planes away and ran those straight into the ground at full throttle.
Never thought I would get back in to planes again but they are so easy to build now and waaay chesper.
 

Kaona

Member
There are relevant factors not included in the Calculator that you are using that would seriously effect the actual maximum speed. The most serious omission is the coefficient of drag for the airframe itself.
As the drag coefficient can vary considerably subject to the aircraft design so will the actual maximum speed. As an example to consider would be a biplane and a WWII monoplane fighter design. Both could weigh the same and even have the same wing loading but the speed difference with the same power plant would be considerable.
I also build and sell RC models though I do so with fixed wing models only! If you are needing to evaluate a single motor across a wide variety of different aircraft models, (bulk purchases for best pricing can reduce the variety of inventory for a small manufacturer), you can vary the prop specifications as well as the battery size and cell count to give the required performance figures.

In your original post you were searching for ways to easily reduce the maximum speed of the model. The simplest method is to underprop the motor so that at maximum throttle the prop generates the required maximum thrust JUST!
If you are selling the setup under you require the end user to miscalibrate the throttle for correct operation I can assure you that the proper calibration will almost never occur and you could be facing a reputation destroying product and possibly a large number of warranty complaints or claims.

Just my opinions of course!

Have fun![/QUOT

I can completely understand that.
Set up I proposed was originally for an f-35 Park jet at 22 oz.
I was more just curious as to what the effects might be in this mini scout.

The only planes that I do make for sale are Park Jets.

I'm just kind of messing with this scout to see what its limits are. It flys pretty good but kinda used to Park jet speeds.

I can calculate the coefficient of drag based on the area and profile of the plane but it's only got an under cambered wing and not sure how to take that into consideration. Any word on that?
 

mrjdstewart

Legendary member
funny, been talking about mini-scouts all day. built more than i can count, prob 30+ and have 3 hanging on the wall as we speak. :unsure:

20200422_170901.jpg


NO WAY!!!!! is a min-scout gonna do that speed. i love your enthusiasm but question your sanity? :LOL:

as mentioned above there are soooo many reasons why this will not happen. if you want to build something that fast, and that size, there are lot's of other options.

please don't take this wrong, but from your question i would guess you are new at this?

flying at that speed is not easy, takes serious concentration and commitment, and has a nasty possibility on failure. even the smallest plane at that speed is something to be afraid of.

i fly very fast things and if that is what you want, there are a lot better options.

20200325_162504.jpg


be safe,

me :cool:
 

Kaona

Member
I had a RCP V5 f-16 park jet scaled down to 90% with a pretty hot setup that read 128 miles an hour on the GPS but that was with the weight of the GPS on it and I'm sure it went a bit faster than that without the GPS unit.
And yeah you're right about one thing scary fast. And very touchy/responsive.
Seemed to glide forever.
 

Kaona

Member
I don't know anything that I haven't done yet.
Like making a mini scout go too fast just to see what happens. Haven't done that yet
If I wreck it no big deal I'll just build another one it probably won't try it again because I'm sure it's going to fail I just want to watch it do so. And to see just what it took.

I know this is not the platform for speed but don't you think it would be fun just to see what it does?