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Jan 15, 2010, 01:34 PM
Registered User
Thread OP
Discussion

Epp version of great planes vfo


Technically this is not a new design, but it is a scratchbuilt.

I bought the Great Planes VFO kit from Tower Hobbies,
http://www3.towerhobbies.com/cgi-bin...?&I=LXXYL8&P=7
and basically traced it onto 9mm EPP. I had read reports that the kit was pretty fragile and I wanted to try to make something that would handle a little more abuse.

I am only posting this in the scratchbuilt forum in case someone else would be interested in trying this fun little plane in EPP.

I was able to leave out all of the triangular bracing required on the 3mm depron
model, so I still ended up with a 4.5 oz. model before adding radio gear. Except that this model was made from a much more robust 9mm EPP.

The final set up was
1700 KV blue wonder motor
9 X 4.7 no name prop from Hobby CIty
four HXT 900 servos
CC25 ESC
2S rhino 610 LIPO
Futaba 6 ch. 2.4 RX

With the Rhino battery the RTF weight is 10 oz.
I could have cut some weight by using 5 gram servos and a smaller battery.

This is basically a no wind or indoor flyer. I flew it in a slight 3mph breeze and had difficulty taking off and landing. It lifted off quite nicely in my shop, but in the breeze it wanted to fall over before lifting off.

The EPP is very durable. I had five pretty good ground strikes while flying it the first time but I just picked it up and hand launched it again. The only thing that broke was my prop saver.

I can't wait for a calm day.
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Jan 16, 2010, 09:02 PM
RC Flyer
Patsy 2 Shoes's Avatar
Hi TD

I guess great minds like yours and mine work the same .

I made a copy of the VFO in 8 MM EPP as well .I made it a little smaller and have little success with it so far .I saw the videos but guess the guy is a much better flyer than myself .

Our usual large gym will not be available for most of the season so we have to use the small gym which gives me almost no room for error with a new airplane to take off vertically.

It has been about a week and I have been waiting for the wind to stop so I can get to see if this thing will fly on it's own .I have to learn to harrier it before going back to the gym .

Thanks
Charlie
Jan 17, 2010, 06:41 AM
Registered User
Thread OP
Hi Charlie,

Your VFO looks pretty good.
What was your final weight RTF

Mine actually flies pretty well in some wind. It is just impossible to take off and land vertically in any wind at all.

You might want to paint your canopy a contrasting color.
Being orange like the tips will make orientation even more difficult.

Let us know how it works. The EPP is definitely much more durable
than the 3mm depron that the kit is made out of.

Tim
Jan 17, 2010, 06:49 AM
Registered User
Thread OP
Oh, it also looks like you did not use any bracing.
You may get a lot of flex when flying.

Around the bottom, or aft end of the plane, I glued small plywood squared on the wings and then ran some unwaxed floss through small holes in the plywood all around the plane.
After putting a drop of CA on each of the places where the floss went through the plywood I ended up with a very stable assembly with almost no added weight.

You can see this in the pictures.

Tim
Jan 17, 2010, 11:15 AM
RC Flyer
Patsy 2 Shoes's Avatar
Hi Tim

Here are some of the specs for my airplane .

25 inch W.S.
28 1/2 inches long
8 mm EPP
6 channel Corona radio
4 ,9 gram servos
3s 500 MAH lipo
12 Amp ESC
22M-1000 Electrifly Rimfire motor
AUW ready to fly 11.5 OZ

I am using a Hitec 7 channel radio to get the elevon / rudder rotation that you see in the previous picture.

My original conception was like yours in that I wanted a durable EPP version of the VFO and in a Blue Wonder size .I thought a few inches smaller than the depron kit would do it .

When it was completed I found out I did not have enough power to lift it off my basement floor .At this point it weighed in at about 10 1/2 ounces if I remember right .

I added a larger motor ,battery and ESC thus it got a lot heavier .This got it off the floor but I am not sure this is the best combination .I will have to review this again .

The first thing I have to do is try to fly it staright and level and try to get it to Harrier properly.I am here in New York and the weather here has been miserable so it will have to wait.

Charlie
Last edited by Patsy 2 Shoes; Jan 17, 2010 at 12:18 PM.
Jan 17, 2010, 11:26 AM
RC Flyer
Patsy 2 Shoes's Avatar
Hi Tim

You mentioned bracing (always a concern with foamies).I have developed a trick I have used and it has been very successful on planes like this .

I did not need any bracing on this airplane .I think it has the right amount of flexibility and ridgity at the same time .The trick is to make it ridgid enoght to have control and be flexible enough to take a beating.

Look at the picture of my airplane and you will see a cross bracing at the rear that ties in the wings and the upper and lower rudders .

The CF rods are 2 MM and the foam sanwiches are 2 pieces of 8 MM EPP and 1 3/4 square .

Charlie
Jan 17, 2010, 11:38 AM
RC Flyer
Patsy 2 Shoes's Avatar
Hi Tim

Here is an illustration of the method for making this type of bracing .It was done on a differant airplane but the same methods apply.

The key thing is to use a fair amount of cement between the foam pads and compress them good and tight until they are about 75 % of their original thickness .Clamp them tight and let dry overnight .

You will find this is a very strong and light method of bracing .It also avoids the complication of external bracing .


On this particular airplane all the verticle rods were round and all the horizontal ones were flats laid vertically for stength.

Here are some pictures.

Charlie
Last edited by Patsy 2 Shoes; Jan 17, 2010 at 12:04 PM.
Jan 18, 2010, 06:44 AM
Registered User
Thread OP
That is interesting Charlie.
Looks like it should do the job.
Thanks for the tip.

On a side note, mine was made out of 9mm EPP and is larger but came out lighter than yours. Even though we used basically the same equipment. You must have had a denser EPP than I used. Do you remember if it is 1.3 or 1.9 PSI density?

Tim

Tim
Jan 18, 2010, 11:48 AM
RC Flyer
Patsy 2 Shoes's Avatar
Hi Tim

The foam is 1.3 but it is stiffer and heavier because it is cut with a hot wire and has a hard (and heavy crust on it ).My supplier saws most of his sizes below 8 MM and they are fuzzier and do not have the crust from the burning operation.

I could be mistaken about the exact weight because when I did not get liftoff I immediatly went to the heavier motor and batteries .I may not have carefully weighed it when I initially installed the blue wonder .As I said I intend to revisit the power reqirements for liftoff .

I am anxious to get it outside in the calm weather to get it to fly straight and level first .

Beyond that I am anxious to try 2 gyros in it .I would imagine that would help stabilize it on take off and landing .

I have 2 inexpensive gyros that have worked wonders on other foamies ,making them great flyers in even very heavy winds .

Need more time and better weather for this project.
Charlie
Jan 22, 2010, 06:22 AM
Registered User
Thread OP
Hey Charlie,
There doesn't seem to be a lot of interest in this particular plane.
Have you flown yours outside yet?

I want to get some videos but my videographer (wife) has been ill
and unable to get out in this crummy weather.

Tim
Jan 22, 2010, 09:28 PM
RC Flyer
Patsy 2 Shoes's Avatar
Hi Tim

I did get to fly it outdoors yesterday .It was very nose heavy and I had all I could do to keep it's head up .I did get it up a ways and did loop it and got it to twist like a cork screw .That is it's most outstanding manuvour ,it's lighning like rolling ability .
Remember I have a 6 channel reciever and a 7 channel transmitter and when you get that lower rudder to kick in with the elevons great things happen .

My hands were too cold to try to move the CG after 2 flights I had to finish up with another plane I could use with my gloves on .

In regards to the lack of interest in this airplane I have witnessed that no one has seen it until I tried to fly it .YThis is something really differant and the word will have to get around .I am not surprised that there has not been more activity on this forum .

We will keep at it and they will come.

Charlie
Apr 11, 2010, 10:15 AM
just Some Useless Geek
Well, I'm for sure interested. Tim, that EPP coloring is just fantastic. You stinker! You make the rest of us look like pikers, without doubt. You suck! Heh.

I'm thinking about an EPP version of this plane a la RCFoamFighters. You know, laminate up two sheets of 3 mm with a fiberglass or nylon weave in between. The resulting 6 mm sheet will be plenty stiff and capable of handling nearly any crash, particularly if the leading edges are all taped up with 3M Extreme tape. (A gift from heaven, BTW. Many of my planes have taken nasty impacts with Other Objects and walked away from it because of that tape.)

A buddy of mine got a copy of the VFO as a door prize at a recent Fun Fly and started building it before he realized that none of his digital radios had sufficient mixing capability to fly this thing to its potential. So, he gave it to me. I'll finish it and fly it, but I want one that I can fly outside without being concerned over damage. The EPP laminate seems like the ideal solution. What say y'all?
Apr 13, 2010, 06:18 AM
Registered User
Thread OP
Quote:
Originally Posted by A Useless Geek
Well, I'm for sure interested. Tim, that EPP coloring is just fantastic. You stinker! You make the rest of us look like pikers, without doubt. You suck! Heh.

I'm thinking about an EPP version of this plane a la RCFoamFighters. You know, laminate up two sheets of 3 mm with a fiberglass or nylon weave in between. The resulting 6 mm sheet will be plenty stiff and capable of handling nearly any crash, particularly if the leading edges are all taped up with 3M Extreme tape. (A gift from heaven, BTW. Many of my planes have taken nasty impacts with Other Objects and walked away from it because of that tape.)

A buddy of mine got a copy of the VFO as a door prize at a recent Fun Fly and started building it before he realized that none of his digital radios had sufficient mixing capability to fly this thing to its potential. So, he gave it to me. I'll finish it and fly it, but I want one that I can fly outside without being concerned over damage. The EPP laminate seems like the ideal solution. What say y'all?
Thanks AUG

I never tried the laminate idea before. Sounds like the best of both
worlds using EPP and getting lightweight rigidity.
I will have to give that a try.

Keep us informed about your results.

Tim
Apr 13, 2010, 07:13 PM
Expo is built into my thumbs
Hance's Avatar
Looks like it might be a fun project does anybody have a set of plans or can you point me to them ? What kind of mix do you have to run on the radio to control it? It looks like that part might get a little complex.
May 11, 2010, 08:57 AM
Registered User
I also made an EPP VFO out of 1.3# Epp. At 12.7 ounces it is a bit heavier than these on this thread but it isn't too bad. I had a blue wonder on the original 3 mm VFO and when I switched to the EPP, the motor just wouldn't do it. The EPP model has a Super Tigre 370 and a 3 cell 800 20C battery pack on it. This combo works real well and I get nice long flights. I take it out at dawn and then again in the evening when the winds are gone. I still don't get many vertical landings (maybe 1 out of 8 on average), but I seldom have any repairs. And that only happens if I come down hard on the nose which, fortunately that does't happen much anymore. I am getting my comfortable with it but I have a long way to go to get good at landings. I used string rigging to help it hold its shape. RCNutt


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