McFoamy-G5

[Madratter]

Howdy:

I just got Realflight 6 the other day, and I'm loving it. One of the things I really like about it compared to Phoenix is the capability for users to develop content.

I downloaded the McFoamy-G5 model that was created under Realflight g5. I really like this model, because I own a Twisted Hobbys 32" Extra 540, and they should fly quite similarly. Thanks to those who created it!

That brings me to my question. The flight physics has changed in Realflight 6 and the model no longer flies quite right. For example, I have had to move the center of gravity forward about an inch.

Changes in the flight modeling also affect rudder authority, and it clearly has in this case, with the rudder now being way too effective.

Has anyone updated this to fly correctly under Realflight 6? I'm working on it, but I'm sure someone with more Realflight experience than me can probably do a better job, and hopefully, already has.

Thanks!

 

[jeffpn]

Hey there. Welcome to my house! I have contacted the guy at Western Michigan a while ago to get accurate component weights on the McFoamy. He said with the holidays, he is very busy. I haven't heard back from him yet.

You are right - there is a HUGE difference in performance in the McFoamy in RF6. I haven't done anything to update the physics. Flexible did the original flight physics on that model. I don't know when it will be addressed for the McFoamy. I'd like to completely redo the flight physics. I want to start with accurate component weights.

 

[Madratter]

Thanks for the welcome.

It should be possible to estimate the component weights of the EPP parts rather closely. If it is like most models this size, the EPP is 9mm, so given the density of the foam and the area of each component (which I assume, perhaps incorrectly you can get from whatever 3d program was used), very close to accurate weights should be able to be figured.

As for the other parts, these foam models tend to use the same kinds of Servos, Escs, Props, etc. So obtaining those weights is usually pretty easy. I can find a bunch of them. For example, you would typically use a 9g servo for the ailerons, and 5g servos for the elevator and rudder. The motor is probably around 24 grams if it is a 1500 kv. A 10 amp ESC would probably way in at about 9g. The prop is probably a 9x4.7 sf. I haven't been able to run down a weight for that. The battery is probably something like a 2s 460 and that would weigh around 30g including wire and connectors. A typical receiver would be something like an Orange 6 channel which is around 9.8g or 3.7g if the case has been removed.

Anyway, I'm guessing at what they use based on my experience with a similar model. But I'm probably pretty close.

Actually a hugely important variable is exactly where and how people decide to mount the hardware because of what it does to the center of gravity.

Another variable is how much glue and the type of glue people use to build these. If they use welders instead of a glue gun, it tends to be lighter. They can also be built with CA but that isn't a good choice normally, because of durability reasons. At any rate, the glue is a non negligible part of the weight. You might use a 1/4 to 1/3 of a tube of welders building one of these. A tube is 1 oz, so that is an additional roughly 7g to 10g of weight.

Hopefully, something in there was a help.

 

[opjose]

Thanks for the welcome.

Anyway, I'm guessing at what they use based on my experience with a similar model. But I'm probably pretty close.

Actually a hugely important variable is exactly where and how people decide to mount the hardware because of what it does to the center of gravity.

EXACTLY!

The sim models the mass distribution and the effects of such.

That is why the better physics models incorporate properly placed components, counterbalances, etc.

Thanks for the welcome.

Another variable is how much glue and the type of glue people use to build these. If they use welders instead of a glue gun, it tends to be lighter. They can also be built with CA but that isn't a good choice normally, because of durability reasons. At any rate, the glue is a non negligible part of the weight. You might use a 1/4 to 1/3 of a tube of welders building one of these. A tube is 1 oz, so that is an additional roughly 7g to 10g of weight.

Hopefully, something in there was a help.

For most of my models 30g of glue is less than the weight of wire ties I put in the plane...

But for small light foamies... that's a BIG deal.

I was working on a 9.5" wingspan Slick 540, where a 10-16g difference in weight had a huge effect on the behavior of the plane.

I no longer use a glue gun as a result... I've had fairly good luck with medium CA and a light application of white ( Elmer's ) glue where needed elsewhere.

 

[flexible]

I have already looked at the Mcfoamie, and concluded that it can not be made right in RF6, without a new and improved prop wash up date from K&E. It is my opinion that there will be NO real world flying foamies in RF6 untill then. I have no planes to waste anymore time trying to edit 3d foamies for RF6, so they are worth flying using broken tools. All my 3d foamie edits are in a holding pattern.

 

[jeffpn]

Holding pattern. I get it!!

 

[Madratter]

I have already looked at the Mcfoamie, and concluded that it can not be made right in RF6, without a new and improved prop wash up date from K&E. It is my opinion that there will be NO real world flying foamies in RF6 untill then. I have no planes to waste anymore time trying to edit 3d foamies for RF6, so they are worth flying using broken tools. All my 3d foamie edits are in a holding pattern.

Ouch, not what I want to hear.

For what it is worth, I found a post indicating that the foam parts for the McFoamy are 80.5 grams.

http://www.rcgroups.com/forums/showpost.php?p=15740664&postcount=7

 

[jeffpn]

I am by no means experienced in editing aircraft. Try this out. I don't know what an appropriate battery/motor/prop combination should be. Maybe this will be good for a starting point.

 

[Madratter]

I am by no means experienced in editing aircraft. Try this out. I don't know what an appropriate battery/motor/prop combination should be. Maybe this will be good for a starting point.

Ok, thanks Jeff!

 

[Madratter]

Edited McFoamy for RF6

I have now extensively edited this aircraft to fly better under Realflight 6. It isn't perfect, but in my opinion it is now way better than it was. Changes are too numerous to mention.

 

[jeffpn]

I like your McFoamy better. It still feels like the rudder is on a stick. I don't know if you know what I'm trying to say. It can really whip.

 

[Madratter]

I like your McFoamy better. It still feels like the rudder is on a stick. I don't know if you know what I'm trying to say. It can really whip.

I think I do know what you mean. The rudder is simply to effective. For example, it knife edge loops way to easily.

 

[Madratter]

Here is my latest edit of this aircraft for Realflight 6. Changes from my last edit are less effective rudder, more propwash, and less back torque.

I'm also attaching a recording I made using this AV in Realflight 6. I used the swap file, Indoor ITESM Toluca. I was flying a very specific pattern I was practicing, and was not just messing around. You can view it with other airports, and some of them are even interesting viewpoints. But to see how I was using all the space, etc. you'll need the right airport.

I'm not the hottest pilot in the world, but I do think it shows some of what the plane is capable of in RF6 now that it has been edited.

 

[jeffpn]

If you're happy with your edit, post it to the swaps. I'd save it under a better name, though. I'll try it in a few, though I'm no expert.

 

[Madratter]

I'm not totally happy with it, but I do think it is worth posting at this point if you try it and give me the go ahead.

At least subjectively, the prop wash model does seem a bit messed up. I have compensated to the extent that I know how.

In my opinion, even with that problem, it blows any of the foam 3d planes in Phoenix out of the water.

An important point is that I have not flown this particular plane in real life. As such, I have edited it to fly as close as possible to my 32" Edge 540 which is similar.

 

[jeffpn]

It would be interesting to get the opinion of Eugene or WMParkFlyer. I know WM is busy filling holiday orders. Maybe we'll hear from him after Christmas.

 

[jeffpn]

The rudder seems so jerky. One small movement of it, and the plane just whips to the side. I don't own a McFoamy either (I've never owned any foamies), but it can't be right. To me, it doesn't look right or feel right. KE's SBach from EP8 doesn't have the rudder whip I'm talking about. To try to get the McFoamy to fly right in EP6, I simplified the physics to try to match the types of physics KE does. I know flexible likes to define movable pods, etc., in order to match the precise shape of the wing and tail surfaces. That's how he did the physics for the original McFoamy, and it flies well in G3 thru G5. I don't know if it's necessary to go through all that trouble. I don't see KE doing that much, if at all. Bottom line: something is wrong, but I don't know what.

 

[Madratter]

The rudder seems so jerky. One small movement of it, and the plane just whips to the side. I don't own a McFoamy either (I've never owned any foamies), but it can't be right. To me, it doesn't look right or feel right. KE's SBach from EP8 doesn't have the rudder whip I'm talking about. To try to get the McFoamy to fly right in EP6, I simplified the physics to try to match the types of physics KE does. I know flexible likes to define movable pods, etc., in order to match the precise shape of the wing and tail surfaces. That's how he did the physics for the original McFoamy, and it flies well in G3 thru G5. I don't know if it's necessary to go through all that trouble. I don't see KE doing that much, if at all. Bottom line: something is wrong, but I don't know what.

What I have tried so far was restricting the deflection of the rudder and making it smaller (but still centered to reduce coupling).

I don't have EP8 so I can't look at how KE did the SBach. If you post a variant with what you just tried, I can look at that and see if I can set that up better than what I was working with.

I will say that the rudder was originally ridiculous without the edits I did. It has been tamed quite a bit with the changes I made. It still isn't right, but the rudder does have more authority than you are probably used to.

At least now, I can fly the maneuvers I was doing in the recording without getting totally frustrated.

 

[jeffpn]

I'm toying with the idea of redoing the physics totally, basing it on the physics of the SBach. I doubt it will happen today or tomorrow, but maybe the next day. I'm sure it still won't be flex-approved, but I don't think it'll have the rudder whip. I'll post it here before I do the servo and push rod animation, to see what you think. When or if you like it, I'll animate the servos. That's only eye candy, anyway, but it's set up to allow for it.

 

[Madratter]

I'm toying with the idea of redoing the physics totally, basing it on the physics of the SBach. I doubt it will happen today or tomorrow, but maybe the next day. I'm sure it still won't be flex-approved, but I don't think it'll have the rudder whip. I'll post it here before I do the servo and push rod animation, to see what you think. When or if you like it, I'll animate the servos. That's only eye candy, anyway, but it's set up to allow for it.

Ok. I'll be looking for it. That Sbach should be a reasonable starting point. In the meantime, I am enjoying the McFoamy even if I'm not totally happy with it the way I have it modified.

One thing about this process, it has made me jump into the deep end in terms of editing the physics. I have learned a lot about it already for having had RF for less than a week. I already have 14 and a half hours on the sim.