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Dec 14, 2019, 01:13 PM
Aeronautical Research Flyer
Rhea's Avatar
That's looking a lot like this.
It's about 6 oz. so heavier than yours with a bigger motor and prop.
It flys very well as I would expect yours to do with your motor and prop.

You won't need the KFM but you will need some kind of spar to stiffen the wing. It may be better to make the wing flat (with no dihedral) and use a piece of flat carbon fiber for a spar.
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Dec 14, 2019, 01:41 PM
IMO ( In My Opinion ) →
balsa or carbon's Avatar
Quote:
Originally Posted by Topher01
I took everyoneís advice and just started building. I stole a bunch of ideas from the simple delta but tried to give it some aesthetic changes and added dihedral like the paper airplane example you linked. Itís 126g with everything including the 450mah 2s as pictured but no kf step. Adding a second motor would add 16g if the battery could handle it. Otherwise Iíd have to go up to a 550mah 3s which would add a bit more. Is there a formula or calculator to determine the wing loading and thrust requirements? Iím at a stage where I can still trim the design down if necessary.

I was looking at it and I could do two motors divided by a v stabilizer by widening that prop slot.

Or just buy a different motor and prop I guess would be an obvious solution as well haha
Yes , I'm glad you're going for it !

The problems I see are :

1) the high wing loading : too much weight and not enough wing area . High wing loading forces a plane to go fast in order for the wings to generate enough lift to become & remain airborne . A delta with the same wingspan will have much more wing area .

2) compared to a larger airframe , a smaller airframe will be more agile . That's great if you are experienced and want to do a lot of stunts ..... but not if you are a beginner who just wants to stay in the air .

3) a flying wing with a shorter chord ( high aspect ratio ) will be much more-sensitive/less-stable and difficult to set-up/tune for pitch .... than a longer chord ( low aspect ratio ) delta .

Go ahead and finish your plane and fly it , if it turns out to be difficult/impossible to fly .... try a larger Simple Delta next .
Dec 14, 2019, 01:43 PM
B for Bruce
BMatthews's Avatar
Topher, what you have seems fine. But a couple of hints.

First off it's obviously now a swept flying wing. Not a delta at all. But it sounds like you've figured that part out already….

Next up is I'd suggest making the prop opening a little wider. The slot like that with the prop running in it will sound like a siren because the slot is so narrow. making it a little wider front to back and keeping the most room between the prop and any edges will help cut the noise down a lot.

Flying wings like this tend to be very sensitive to pitch and just so-so sensitive to rolling. And the portion of the control surfaces near the center will work more as elevators than it does ailerons. So a good way to make things easier on you and to better harmonize the control response between pitch and roll is to make just the outer half of what you show in the pictures actually movable. You can do some of the harmonizing with the Tx setup too. But it makes life easier if you give the physical design a better fighting chance to start out.

At that weight and size I think you'll be OK with the motor and prop. The motor is pretty punchy on a racing quad after all. The question will be how much air is moved by that small a prop. But since you're learning to fly a fixed wing you don't really want a powerful setup to start with. So I'd say carry on and give it a go.

I'm assuming dollar store paper clad foam board is the material? Assuming so you should not need the KFM double layering. And if it does crash and fold up it's only a few minutes to make a new wing and move the stuff over. Just keep in mind that you're likely going to find that the real thing is a lot more nervous in the air than the sims would suggest. Small models are often far more nervous than big models. So when you set this one up don't use very much control throw. I'd suggest starting with maybe 20 degrees either side of neutral. And even less for the elevator function. More like 10 degrees for pitch. That'll mean playing with the mixing ratio or control volume on the elevator channel.

Good luck with the flying!
Dec 14, 2019, 01:45 PM
B for Bruce
BMatthews's Avatar
And I see BorC posted a response while I was typing mine. That's gold class advice from him if this version doesn't work out so well. And only another buck for a sheet of foamboard ! ! !

If you do go with the longer chord version he shows I'd also switch to a nose mounted motor. It would be easier to achieve the proper balance point.

Another option which can be easily built from a single piece of foamboard is the Nutball. Might be an option for you to consider. Normally they are what would be considered a highly maneuverable model. But if you shift the hinge lines to make the controls about 2/3's the sizes shown and keep the throw angles smaller they can also be a decent sort of trainer.

For your little motor and gear you'd want to make the diameter more like 18 inches. Small to keep it light but still a good amount of wing area to aid with keeping it fairly slow.

Check out You Tube for some nutball flying with the search terms " nutball model airplane".
Last edited by BMatthews; Dec 14, 2019 at 02:09 PM.
Dec 14, 2019, 02:14 PM
Registered User
Thread OP
Ok no I didn’t understand the delta vs swept wing clearly before but I understand now. Thank you! So I basically need to cut the control surface width in half on each side and use the outer section. That way the servos have more resolution and the balance between P and R is better.

I have another sheet of the elmers Foamboard in 20x30 that I’m going to start building a simple delta on in case this guy doesn’t work out. I’ll put a 2205 2550kv with a 5045 triblade on it.
Dec 14, 2019, 02:17 PM
Aeronautical Research Flyer
Rhea's Avatar
I didn't think of the Nutball until Bruce mentioned it. That is a lot of fun too.
Dec 14, 2019, 02:24 PM
Registered User
Thread OP
Buddy of mine gave me these cf arrows. So I figured Iíd build a stick trainer out of one too. I figure if I have 3-4 planes to fly my odds are better lol! I was going to try cutting out an airfoil wing for it with my hot wire cutter. I have some 2Ē pink insulation that I wanted to use. Iím not sure if there is a particular set of plans that are better. I have a 2205 2550 or a 2212 2000 motor I could use.
Dec 14, 2019, 02:43 PM
IMO ( In My Opinion ) →
balsa or carbon's Avatar
The Nutball Bruce mentioned can be a good slow flying trainer if built with low wing loading . Here's a video of one I built with very low wing loading :

26" Nutball RC plane (1 min 49 sec)




Building a Simple Delta with your second sheet of foam board is a good idea , make it the full 30" wingspan and 20" root chord for maximum wing area ..... and don't add any reinforcement ( like a KFm doubler ) that will add unnecessary weight .

If you ever order a motor to be used for a fixed wing airplane that you want to fly slowly , order a low/medium kv motor that can swing a bigger prop . Lower RPMs with a bigger prop are like driving your motorcycle slowly in first gear ( easy ) . Higher RPMs with a smaller prop are like trying to drive your motorcycle slowly in 3rd or 4th gear ( not so easy ) .

Here is my favorite motor for slow flying park flyer sized airplanes : https://www.amazon.com/hexTronik-24g.../dp/B00URCHXEW it can use a 9 x 3.8 prop on 3S .

This is my second favorite : http://fancyfoam-com.3dcartstores.co...otor_p_35.html
Dec 14, 2019, 02:59 PM
IMO ( In My Opinion ) →
balsa or carbon's Avatar
Quote:
Originally Posted by Topher01
Buddy of mine gave me these cf arrows. So I figured Iíd build a stick trainer out of one too. I figure if I have 3-4 planes to fly my odds are better lol! I was going to try cutting out an airfoil wing for it with my hot wire cutter. I have some 2Ē pink insulation that I wanted to use. Iím not sure if there is a particular set of plans that are better. I have a 2205 2550 or a 2212 2000 motor I could use.
One of those arrows would make a good wing spar .

The conventional winged beginner plane I recommend most often is the EzFly . The EzFly is very stable and can be slow flying if built with low wing loading . And it is a pusher so it protects the motor/prop if crashed nose first .

Here is a video of one of my EzFlys , built with low wing loading :




Copy of EzFly with under-cambered wing (1 min 57 sec)
Dec 14, 2019, 06:18 PM
Registered User
Thread OP
Here is my favorite motor for slow flying park flyer sized airplanes : https://www.amazon.com/hexTronik-24g.../dp/B00URCHXEW it can use a 9 x 3.8 prop on 3S .

This is my second favorite : http://fancyfoam-com.3dcartstores.co...otor_p_35.html[/QUOTE]

Ok I attempted to fly the scout on 3s since my 2s packs were dead and yep.. I believe my lack of a proper power system is preventing me from finding any of this enjoyable.. I ripped the wing in half because I couldnít get a happy medium between throttle and pitch. It was either pointed north or south the whole damn flight so this motor you linked from amazon, is it common to a lot of designs? IE I could use it on the delta and afterwards move it to a trainer or 4 channel plane? I cut out Magnum Reloaded the other night.. could I use it on that? Thanks for the help today!

Also decided to add elevons to the trailing edge of the first wing I built rather than cut them out of whatís there. I figured Iíd just put them on a tape hinge. I believe that would technically add surface area to the wing?
Dec 14, 2019, 06:55 PM
IMO ( In My Opinion ) →
balsa or carbon's Avatar
That Amazon motor ( 24 gram hexTronik ) is a good multipurpose motor for slow-medium parkflyer-sized planes . The hexTronik 24 gram is available in several KV's : 1300kv , 1500kv , 1700kv and 3000kv .

The 1300kv and 1500kv are good for slow-medium speed flyers : I use them on my 40" FT Old Fogey-ish , my standard size EzFlys , my 40" Simplest Simple Delta slow flyer , my 32" Yak 55 3D plane ( will climb straight up ) , my Electrifly Flylite , my Big Wheel delta , etc .

The 1700kv is good for parkflyers where you want a little more zip , like my 30" Simplest Simple Delta .

The 3000kv is good for speedy parkjets like my F-15 ..... probably gets it going up to 50-60 mph .

If you look at the early FliteTest build videos ( Nutball , FT Flyer , etc ) , they often used the hexTronik 24 gram motors .
Here is Josh's build video for the FT Nutball , he uses a 1300kv hexTronik motor :


Flite Test - Nutball - SCRATCH BUILD (11 min 44 sec)
Last edited by balsa or carbon; Dec 14, 2019 at 07:37 PM.
Dec 14, 2019, 07:07 PM
Registered User
Thread OP
Guys, I’m terrible at the forum and doing the quote reply bit. But I’m reading every post in this thread several times and I really appreciate you guys taking the time to help me with my newb questions and mistakes!
Dec 14, 2019, 07:22 PM
IMO ( In My Opinion ) →
balsa or carbon's Avatar
Quote:
Originally Posted by Topher01
Guys, Iím terrible at the forum and doing the quote reply bit. But Iím reading every post in this thread several times and I really appreciate you guys taking the time to help me with my newb questions and mistakes!
We've all been there ( newb-land ) and done that ( made mistakes , crashed planes , etc ) .

It's very satisfying to help a newb and see them achieve success ! Here's the thread of a newb in England who struggled at first but ultimately had successful flights with his home made planes :
https://www.rcgroups.com/forums/show...-XK-DHC-2-A600
Dec 14, 2019, 07:49 PM
Registered User
Thread OP
Ordered two of those motors. Are there any specific sized or branded props I should get to pair with them? I ordered a pair of 2s 650mah batteries as well. At least now I’m giving myself a reasonable chance of success I guess.
Dec 14, 2019, 09:03 PM
IMO ( In My Opinion ) →
balsa or carbon's Avatar
Quote:
Originally Posted by Topher01
Ordered two of those motors. Are there any specific sized or branded props I should get to pair with them? I ordered a pair of 2s 650mah batteries as well. At least now Iím giving myself a reasonable chance of success I guess.
For the 1300kv hexTronik 24 gram motor I like the APC 9 x 3.8 SF prop : https://www.amazon.com/Slow-Flyer-Pr.../dp/B0006O6S38

On a lightweight plane and for mild flying : that motor will be fine on 2S , but it can handle 3S . I most often use a 1000mAh 3S battery on my parkflyer-sized planes . https://hobbyking.com/en_us/turnigy-...lipo-pack.html

Those motors come with a prop saver , have you used a prop saver before ?
Last edited by balsa or carbon; Dec 14, 2019 at 09:08 PM.


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