Go Back  RCU Forums > RC Airplanes > Questions and Answers
Reload this Page >

Question about Model Airplane Weight Limits

Notices
Questions and Answers If you have general RC questions or answers discuss it here.

Question about Model Airplane Weight Limits

Old 07-20-2016, 06:56 PM
  #51  
Stick 40
 
Join Date: Jun 2003
Location: quincy, MI
Posts: 1,205
Likes: 0
Received 0 Likes on 0 Posts
Default

Originally Posted by Hydro Junkie
Okay, what do you base that tail heavy comment on? Experienced builders routinely find a way to remedy that issue prior to covering. When I build a boat, in my case sport and scale hydroplanes, I have to balance them to within a very narrow window to prevent blow overs or plowing. Balancing a plane isn't any different, other than the fact that you can place the engine as far forward as you want where I can't in a boat.
when you build a boat?
what does a boat and a plane have in common? one is in the water and one is in the air, boats don't crash into the ground.
most planes are tail heavy, if boats are I don't know about that. but I know a tail heavy plane tend to crash, what does a tail heavy boat do???
Old 07-20-2016, 07:08 PM
  #52  
Stick 40
 
Join Date: Jun 2003
Location: quincy, MI
Posts: 1,205
Likes: 0
Received 0 Likes on 0 Posts
Default

Originally Posted by HighPlains
Don't you know by now that everyone on the forums are experts?

There is one guy that has posted on this thread that I trust without reservation (besides me of course). His depth of knowledge and experience is second to none. It is your job to figure out who.
yup, good luck!!!
Old 07-20-2016, 07:23 PM
  #53  
Stick 40
 
Join Date: Jun 2003
Location: quincy, MI
Posts: 1,205
Likes: 0
Received 0 Likes on 0 Posts
Default

Originally Posted by gregoryshock
I have read that model airplanes tend to have more power per weight/size then a full size airplane. For an example I read that a 40 size trainer plane like eagle 2 was originally powered by a 20. If a person is using the smallest engine stated by the kit specs, how much over the weight limit can one go? My kit says it should weigh between 7 and 9.5 pounds.
I still don't get what I don't understand about this post. I tend to see engine size and plane weight. I know we are all going toward larger engines for a plane. His kit says 7 to 9.5 lbs and he is talking about 40 and 20 sized planes . what did I miss when I stated going with a larger engine? I would go with a much larger than a .40 size engine. just my thouughts!
Old 07-30-2016, 01:46 PM
  #54  
Hydro Junkie
 
Hydro Junkie's Avatar
 
Join Date: Nov 2004
Location: Marysville, WA
Posts: 10,520
Received 130 Likes on 123 Posts
Default

Originally Posted by Stick 40
when you build a boat?
what does a boat and a plane have in common? one is in the water and one is in the air, boats don't crash into the ground.
most planes are tail heavy, if boats are I don't know about that. but I know a tail heavy plane tend to crash, what does a tail heavy boat do???
You obviously have never driven a scale hydroplane in racing conditions. Let me explain it to you:
1) A tail heavy plane will naturally try to climb, a tail heavy hydroplane will also try to climb.
2) A nose heavy plane will naturally try to dive, a nose heavy hydroplane will also try to dive. Due to the hydrodynamic shape of the modern styled sponsons, it will either plow through the water or, in some extreme cases, it will actually drive itself under water
3) A hydroplane works in ground affect air, similar to a low winged airplane. The air under the hull is actually what the boat rides on, not the water, while running at speed
4) A hydroplane uses a bottom AOA of between 5 and 10 degrees, much higher than on most R/C aircraft, again requiring a more precise balancing, considering the average boat is roughly 44" long, 20" wide and weighs 12-15lbs
5) If the hydroplane is not balanced properly and, as stated in #1, the nose starts to climb, the air under the boat will actually flip the boat as shown in this video at about the 45 second point https://www.youtube.com/watch?v=mklxtov4yC4 or in this video https://www.youtube.com/watch?v=zujy5U2QqdY

A hydroplane may not crash like an airplane but they do crash and, in the same way, they can be taken home in a garbage bag, at lease what doesn't sink. As far as I'm concerned, a good day at the lake is a day when the boat runs well and goes home in piece. Does that sound like an airplane, a good day is one that it flies well, lands under control and goes home in one piece? Sounds like it to me

Last edited by Hydro Junkie; 07-30-2016 at 02:05 PM.
Old 08-05-2016, 05:10 PM
  #55  
Stick 40
 
Join Date: Jun 2003
Location: quincy, MI
Posts: 1,205
Likes: 0
Received 0 Likes on 0 Posts
Default

Originally Posted by gregoryshock
I have read that model airplanes tend to have more power per weight/size then a full size airplane. For an example I read that a 40 size trainer plane like eagle 2 was originally powered by a 20. If a person is using the smallest engine stated by the kit specs, how much over the weight limit can one go? My kit says it should weigh between 7 and 9.5 pounds.
lets get back to the question and talk about planes.

yes we are going toward larger engines in planes and the larger engines help balance a plane as they tend to be tail heavy!

I think that is the plus side of the issue, more weight in the nose , may help balance the plane and that is all I was trying to say.

I think I 7 to 9 lb. plane would need a .60, I could be wrong.

sticks
Old 08-05-2016, 05:56 PM
  #56  
Stick 40
 
Join Date: Jun 2003
Location: quincy, MI
Posts: 1,205
Likes: 0
Received 0 Likes on 0 Posts
Default

Originally Posted by HighPlains
Don't you know by now that everyone on the forums are experts?

There is one guy that has posted on this thread that I trust without reservation (besides me of course). His depth of knowledge and experience is second to none. It is your job to figure out who.
thanks

sticks
Old 08-11-2016, 08:26 AM
  #57  
sensei
 
sensei's Avatar
 
Join Date: Jul 2002
Location: SAN ANTONIO, TX
Posts: 2,826
Received 17 Likes on 15 Posts
Default

Originally Posted by Stick 40
I still don't get what I don't understand about this post. I tend to see engine size and plane weight. I know we are all going toward larger engines for a plane. His kit says 7 to 9.5 lbs and he is talking about 40 and 20 sized planes . what did I miss when I stated going with a larger engine? I would go with a much larger than a .40 size engine. just my thouughts!
If one of my kits states it is supposed to weigh 7 to 9.5 pounds RTF then I automatically place it on a strict diet from the first stick to the last, and anything that goes on board. I do this because lighter in fact flies better and from experience I know it can be built between 5 and 6 pounds ready to fly with a smaller power plant and out perform it's heavier counterpart.

Bob
Old 07-15-2018, 03:40 PM
  #58  
gregoryshock
Thread Starter
 
gregoryshock's Avatar
 
Join Date: Mar 2011
Location: Goshen, IN
Posts: 304
Likes: 0
Received 0 Likes on 0 Posts
Default

I worked on the model for a very long time until it appeared that it is no longer worth the time and money to make it fly. I moved on.
Old 07-16-2018, 06:46 AM
  #59  
r ward
 
Join Date: Mar 2018
Posts: 481
Likes: 0
Received 2 Likes on 2 Posts
Default

you ask what does water and air have in common concerning dynamics,......go do some reading about sailboat hull design and the application of foil shaped keels in water compared to the lift a wing generates...... in both cases the term "lift" and their functions are universally applicable and interchangeable.
Old 07-16-2018, 07:51 AM
  #60  
gregoryshock
Thread Starter
 
gregoryshock's Avatar
 
Join Date: Mar 2011
Location: Goshen, IN
Posts: 304
Likes: 0
Received 0 Likes on 0 Posts
Default

I thought about burning the model and posting it on youtube so that people from TF can watch it burn out of disgust. I openly admit now that I was dumb for even thinking that I could build and fly a corsair. Even if my TF P51 ARF flies at all I decided I will not buy another TF model. Both models gave me lots and lots of building issues. Back when I posted this thread I actually thought that with as many airplanes built and flown, the propeller size per weight, per power was scientific. In stead I found trial and error. There is saying that I think you are thinking about me! "You can lead a horse to water but you can't make him drink." But maybe the reason why the horse won't drink is because the water is contaminated. That sums up how this horse felt about the construction of this airplane all the way to the point of creating this thread. Years later and I still feel the same way! The only reason I haven't thrown the model out yet is because my Dad won't let me. I feel that TF had the entire kit booby-trapped and those with lots of experience can work around the trap. It is the only logical explanation I can come up with for those who had success with it. If more planes designed like the way TF did this one I wouldn't be in the hobby at all.
Old 07-16-2018, 11:56 AM
  #61  
DGrant
My Feedback: (4)
 
DGrant's Avatar
 
Join Date: Dec 2001
Location: Clovis, CA
Posts: 2,194
Received 30 Likes on 27 Posts
Default

Originally Posted by gregoryshock
I thought about burning the model and posting it on youtube so that people from TF can watch it burn out of disgust. I openly admit now that I was dumb for even thinking that I could build and fly a corsair. Even if my TF P51 ARF flies at all I decided I will not buy another TF model.
Why the hostile attitude?.. You built the plane, they didn't.

Originally Posted by gregoryshock
Both models gave me lots and lots of building issues. Back when I posted this thread I actually thought that with as many airplanes built and flown, the propeller size per weight, per power was scientific.
It is very scientific. Science must be studied though. Experiments need to happen.

Originally Posted by gregoryshock
In stead I found trial and error. There is saying that I think you are thinking about me! "You can lead a horse to water but you can't make him drink." But maybe the reason why the horse won't drink is because the water is contaminated. That sums up how this horse felt about the construction of this airplane all the way to the point of creating this thread. Years later and I still feel the same way!
It's your call as to what you drink or not. There's no contaminated water in this thread. You've got some very sound advice from several experienced users. Some of which have been successful with their TF Corsairs... and not one of their planes is alike... but those that reported all shared the plane does fly... and then went on to share some of their experience. That tells me there's several ways to make it work. I'm thinking the biggest problem was in your build and it being too heavy... and yes, they can always be built lighter.. it just takes experience.. You'll get that if you keep at it.

Originally Posted by gregoryshock
The only reason I haven't thrown the model out yet is because my Dad won't let me. I feel that TF had the entire kit booby-trapped and those with lots of experience can work around the trap. It is the only logical explanation I can come up with for those who had success with it. If more planes designed like the way TF did this one I wouldn't be in the hobby at all.
The building aspect of this hobby isn't for everyone. There's no booby traps in these kits other then what we create... and yes it takes experience to build these things. There's only one way to get it, and unfortunately the experience you had wasn't what you'd hoped for... but you still got the experience of one kind or another. Listen to your Dad, he's making you keep it for some reason... Dad's know stuff.. Your's does too I'm sure.

It's up to you if you want to go into another area of the hobby... and you might be better off and at least have some fun. I hope you do better with your ARF... but do be aware there's still no magic that applies whether it's an ARF or a kit. They all set-up and finish the same, they all fly the same(relatively close in this case)... and they all use the same type of engine and prop applicable to the size of the airplane. So I just hope you're not going from the frying pan into the fire with an ARF P-51. On the other hand you might do very well with, and I hope you do.

Good luck with it.
Old 07-16-2018, 12:56 PM
  #62  
gregoryshock
Thread Starter
 
gregoryshock's Avatar
 
Join Date: Mar 2011
Location: Goshen, IN
Posts: 304
Likes: 0
Received 0 Likes on 0 Posts
Default

Originally Posted by DGrant
Why the hostile attitude?.. You built the plane, they didn't.
There is so many problems in the kit, that if you built exactly like they say to do it. It will be unsafe to fly! It would take me a really long time to list them all! I've been angry at Top Flite and this airplane for several years and I can't shake the negative feelings.

Originally Posted by DGrant
It is very scientific. Science must be studied though. Experiments need to happen.
Experiments that involve crashing and wasting money. Some of you got a lot more money and time.

Originally Posted by DGrant
It's your call as to what you drink or not. There's no contaminated water in this thread. You've got some very sound advice from several experienced users.
I don't know any of you that well!

Originally Posted by DGrant
Some of which have been successful with their TF Corsairs... and not one of their planes is alike... but those that reported all shared the plane does fly... and then went on to share some of their experience. That tells me there's several ways to make it work. I'm thinking the biggest problem was in your build and it being too heavy... and yes, they can always be built lighter.. it just takes experience.. You'll get that if you keep at it.
If you build it over and over and over and over again. I don't have the money or the patience for it!

Originally Posted by DGrant
The building aspect of this hobby isn't for everyone. There's no booby traps in these kits other then what we create... and yes it takes experience to build these things. There's only one way to get it, and unfortunately the experience you had wasn't what you'd hoped for... but you still got the experience of one kind or another. Listen to your Dad, he's making you keep it for some reason... Dad's know stuff.. Your's does too I'm sure.
We talked about it today and He decided that we should throw it away too.

Originally Posted by DGrant
It's up to you if you want to go into another area of the hobby... and you might be better off and at least have some fun. I hope you do better with your ARF... but do be aware there's still no magic that applies whether it's an ARF or a kit. They all set-up and finish the same, they all fly the same(relatively close in this case)... and they all use the same type of engine and prop applicable to the size of the airplane. So I just hope you're not going from the frying pan into the fire with an ARF P-51. On the other hand you might do very well with, and I hope you do.

Good luck with it.
Dad and I talked about it and He agrees with me. If the P-51 crashes it crashes, we are not repairing. He's just as upset at Top Flite as I am!

My Dad and I have built several airplanes, and some from kits. This is the only one that wouldn't fly at all. But we are not good enough for war birds. That is what the experience taught us. It knocked us off our pestle. I need to get rid of my pride and my feelings but Top Flite stinks and I doubt anyone can ever convince me otherwise. I leave the Top Flite Models to the experts in this forum. It kicked my Butt so hard that I never want to return to it.

The reason I made my very last post in here was to give everyone an update, just letting everyone know that I'm done with the model and it's all over with.

Last edited by gregoryshock; 07-16-2018 at 01:00 PM.
Old 07-16-2018, 01:08 PM
  #63  
gregoryshock
Thread Starter
 
gregoryshock's Avatar
 
Join Date: Mar 2011
Location: Goshen, IN
Posts: 304
Likes: 0
Received 0 Likes on 0 Posts
Default

For the most part all the parts are off it. I'm going to dig out the servos that control the flaps. After that I'm going to burn the model. Good riddance!
Old 07-16-2018, 02:05 PM
  #64  
gregoryshock
Thread Starter
 
gregoryshock's Avatar
 
Join Date: Mar 2011
Location: Goshen, IN
Posts: 304
Likes: 0
Received 0 Likes on 0 Posts
Default

It's over, I burned the wings today. The Fuse tomorrow.
Old 07-19-2018, 06:55 AM
  #65  
r ward
 
Join Date: Mar 2018
Posts: 481
Likes: 0
Received 2 Likes on 2 Posts
Default

Originally Posted by Stick 40
when you build a boat?
what does a boat and a plane have in common? one is in the water and one is in the air, boats don't crash into the ground.
most planes are tail heavy, if boats are I don't know about that. but I know a tail heavy plane tend to crash, what does a tail heavy boat do???
if take a look at any hydro plan it will have a balance point indicated just like a plane has. full size boats, especially sail boats, will have an indicated C/G point on hull form plan it is essential to their sailing "on her lines" and handling. just like a plane flying neutral or flying level with hands off the sticks,...a sail boat will sail hands off tiller when the boat is built to it's proper C/G and well balanced. a sail boat that is trimmed excessively to sail properly will have certain detrimental idiosyncrasies in handling just like a plane.
Old 08-30-2018, 05:30 AM
  #66  
Appowner
Banned
 
Join Date: Nov 2017
Posts: 1,016
Likes: 0
Received 3 Likes on 3 Posts
Default

Originally Posted by gregoryshock
There is so many problems in the kit, that if you built exactly like they say to do it. It will be unsafe to fly! It would take me a really long time to list them all! I've been angry at Top Flite and this airplane for several years and I can't shake the negative feelings.

...................
Next time purchase something in line with your experience. War birds obviously are currently beyond you and your fathers level of skill and understanding. Like flying, building is also a learned skill that takes time and experience. Did you ever, ever go to the local club seeking help?

Top Flight has been around for many, many years. They are a trusted manufacturer. I myself have had numerous TF kits and have helped many others build theirs. The kits today are works of art compared to what we had in the 60's. I think simply you and your father tried to fly before you could walk.
Old 09-02-2018, 09:02 AM
  #67  
udithag
 
Join Date: Sep 2018
Location: Sri Lanka
Posts: 13
Likes: 0
Received 0 Likes on 0 Posts
Default

If you your aircraft's weight to power ratio (kg/hp) value is less than 7, there is no need to worry about and has lot of power. If the ratio is greater than 7, then it would be little bit difficult to take off. From my experience keeping that value less than 7 makes always easy to fly. weight to power ratio = Maximum takeoff weight(kg)/Power (hp)
Old 09-12-2018, 01:37 AM
  #68  
skybolt58
 
Join Date: Feb 2005
Location: ava, NY
Posts: 13
Likes: 0
Received 0 Likes on 0 Posts
Default

ok here is a question, I have the tf 60 gold edition, I intended the O.S. 91FX> with engine and added nose weight it weighs 14 pounds? will that engine work or get a 20cc gas evolution
Old 09-12-2018, 05:59 AM
  #69  
j.duncker
My Feedback: (2)
 
j.duncker's Avatar
 
Join Date: Jun 2004
Location: Sailing in the Eastern Caribbean
Posts: 4,047
Likes: 0
Received 1 Like on 1 Post
Default

Originally Posted by skybolt58
ok here is a question, I have the tf 60 gold edition, I intended the O.S. 91FX> with engine and added nose weight it weighs 14 pounds? will that engine work or get a 20cc gas evolution
If it is the 63 in wingspan Corsair then at 14 lbs it is grossly overweight. If you want to go ahead and try to fly it then get something like an OS 120 AX and fly of a paved strip. But take a trash bag with you.
Old 09-13-2018, 06:03 AM
  #70  
Appowner
Banned
 
Join Date: Nov 2017
Posts: 1,016
Likes: 0
Received 3 Likes on 3 Posts
Default

Originally Posted by skybolt58
ok here is a question, I have the tf 60 gold edition, I intended the O.S. 91FX> with engine and added nose weight it weighs 14 pounds? will that engine work or get a 20cc gas evolution
Which TF 60 gold edition?

The Mustang has the biggest wing area wise. Some 734 sq inches. At 10 pounds it comes in just over 30 ounces per sq ft. Not unusual for a war bird and in fact, in the right range. At 14 pounds you have around 44 ounces per sq ft (and that's if you have the Mustang). Or roughly what a cinder block might have. Could it be flown? Yes! But consider, in order to lift that weight the wing needs to move faster through the air to generate the necessary lift. That also means your stall speed, the speed at which the wing stops flying, goes up appreciably. So your landing speed is going to be higher than normal. And war birds do not like to land fast if it can be helped. Flaps IMHO would be mandatory.
Old 09-13-2018, 07:15 PM
  #71  
the Wasp
My Feedback: (1)
 
Join Date: Sep 2003
Location: VT
Posts: 5,377
Likes: 0
Received 41 Likes on 39 Posts
Default

" (APC"
Originally Posted by skybolt58
ok here is a question, I have the tf 60 gold edition, I intended the O.S. 91FX> with engine and added nose weight it weighs 14 pounds? will that engine work or get a 20cc gas evolution
"14 pounds"

are you sure that is the weight of your plane ??, how did you weigh it ??
if it truly weighs 14 pounds you should buy another engine,, I suggest the Saito 125, most likely it's the lightest engine in it's class (rather 2 or 4 stroke), and it will swing a big prop "16X6, 15X8" (APC), if you use a wood Xoar you would have to go down in pitch by 2 inches "16X4, 15X6",, Xoar props really pull a lot of air..

good luck

Jim

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service -

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.