Nitro2Burn

Hi guys, I'm trying to find a good fast wing profile for my Rivets scale racer. I need something that can fly fast but with decent characteristics as it is still a scale aircraft of 85" span.
any ideas?

Lownverted

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Hi Nitro,

I'm partial to the SD6000 series particularly the SD 6060, 61, & 62. If it were me I'd look at the 6060 for the root and 6061 for the tip. If you want a bit thinner, 6061 root and 6062 tip. I've used them a ton and they are hard to beat. Good luck and pleas post pics!

Red

Nitro2Burn

Thanks very much Red,
I appreciate your help and will keep you up to date on its progress. At this point am still waiting for the smaller plans to see if I am better of scaling them up for the fuse or doing a plug from 3-views and molding from that.
Another question if you don't mind, I see the SD6060 is not a fully semetrical profile, is this better for any reason? As a newcomer to the racing scene I have yet to learn these finer details, I would have thought better penetration from no lift, maybe not so. About the only thing it looks I was on the right path of is I was aiming at around 10% of the wing cord for wing depth.
Byron

pjakew

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Hey Red

At some point I need to get back over to your club and get back into the nitro class racing. I have been busy,but I have not forgotten.

ChrisAttebery

My Feedback: (15)

I used a NACA 66012 on my YS110 powered Strega a couple years ago. The plane picked up about 10mph over the stock wing. You might want a little camber in the airfoil you could try a 66212 instead.

speedracerntrixie

My Feedback: (29)

I've been using the RG 15 on the Macchi designs. Seems to work well and holds speed well in the turns.

tdstaf

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Are you going to race it or sport fly it? There are several airfoils you can use, but really need to know how you are going to fly it to choose one to suit your purpose.

Tim

Nitro2Burn

Hi Tim,
This is being built to be raced here in Australia in our Formula 1 catagory 80-90"span, max 55cc unmodified engine.


Thanks everyone it's all helping along with worldofkrauss to help me check them out.

Lownverted

My Feedback: (4)

Hi Byron,

A fully symmetrical profile must fly at some positive AoA to produce lift. Lift produces drag. A semi symmetrical section can provide an equal amount of lift but with less drag and will usually turn harder. You see the symmetrical airfoils doing pretty well in Q-500 applications, but they have the benefit of much lower wing loading. With heavier birds, I would stick to something with more camber for sure.

Cheers
Red

Lownverted

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Hey Jake,

It would be nice to see you again. The 1/12 scale stuff has fizzled a bit lately so some extra participation would be great. Let me know if you need anything.

Here is the Tsunami I built for this season.

tdstaf

My Feedback: (11)

I'm with Red on this as well. The SD airfoils work well and I have also used the six digit NACA 64a 21001 the four digit 1412 and the five digit 23012. But you need to land fast as these have will tip stall The 1412 turns tighter, but when you pull that hard it bleeds off speed. These work well with 2 degrees of wing incidence and 1 degree of stab incidence using an 11 or 12 percent thick tail surfaces.

tdstaf

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Red the tsunami looks great. What is it about 100". Lol look at the perspective with people in the back ground. The table looks like it's turf on the ground.

Tim

Lownverted

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Tim,

The forced perspective does make it look huge doesn't it....I never noticed that before! It's a bit on the small side actually, only 29" span and 165 sq. in with a O.S. .30 [X(] Lotsa fun in a small package. BTW...it has a 6060 at the root and 6062 at the tip.

Nitro2Burn

Heaps of great info guys thanks. After checking through them all I believe I will be going with the 6060 at the root and 6061 at the tip. Finally Red do you use any wash out? or you find no real need for it so far? I've had a few people here tell me you NEED it but have never HAD to really use it before on kits or scratchies, however I have not built a machine based around speed before.

Tip stalls aren't usually an issue for me as I always do my best to test aircraft stall speeds at height on test flights so I get an idea of what kind of a suicide mission I'm flying before I go slow and low. Though there is always "that time" when you get caught with your pants down (caught by suprise) and you find out how well an aircraft cartwheels along the deck.

tdstaf

My Feedback: (11)

It is always good to run washout on a wing. Especially warbirds and racers. I generally run 2 degrees of washout and use 3 degrees of washout on my racers as your pulling high angles of attack around the pylons. I have seen some violent high speed stalls and there not much left afterwards.

Lownverted

My Feedback: (4)

Nitro,

I'm not with the masses when it comes to the use of washout. I follow a different philosophy when it comes to wing design than many others do. As such your results may vary

I build mostly racers and high performance (faster) type aircraft, F3B(F) gliders, and the occasional 3D type thrown in. None of them have washout....ever. Twist or washout in a wing is induced drag, has an effect on top speed (every little bit helps when racing), and works in reverse if you are inverted. Granted you are not usually at landing speeds while inverted, but if you fly aerobatics you will be at some point. I really like a well behaved airplane all around.


I have found that by careful airfoil tailoring, you get the same effect as washout without the penalties assosicated with it. It typically like to use a thinner airfoil at the tip from the same family. This keeps the air attached at the tip at higher Alpha thus preventing tip stalls. A good example is my Tsunami above. The wing loading works out to be over 28 oz/ft and it lands great with no issues. On a typical warbird, like a P-51 for instance (I've built many Reno racers) I use the same airfoil progression and if you want some extra stability, reflex the ailerons about 1/8" during landing. I'm a big fan of spoilerons for landing instead of flaps too, but thats a whole post to istelf.

Cheers
Red

speedracerntrixie

My Feedback: (29)

I'm with you here Red. I run no washout but will usually move the high point of the tip airfoil forward a tad. Seems to work well so far. Flying sailplanes really heps understanding airfoil theory and parctice.

tdstaf

My Feedback: (11)

That all works well for all out speed. I also design for the general sport Warbird flyer as well and dont need all out speed when there is a maximum time limit or break out time. When I have a chance would like to talk about this in length you guys.

Lownverted

My Feedback: (4)

It works well for all around stuff too. Washout is incedence and can cause trim change with speed, something else I don't like. Drop me a pm if you want to chat, I'll give you my cell.

Nitro2Burn

Tim, Red and everyone else who has contributed,
I have pretty much got the info I initially requested and everything from here on is now part of the learning and still fits the subject so I am happy for you guys to keep the convo going in here also if you like. I understand everyone has different views on a number of subjects and as my grandfather once told me many moons ago, "Free advice is always worth listening to, it is up to yourself to work through it and sift out the BS and whether or not to put it into action"
It seems that so far you guys have produced zero in the BS range and all view points are welcomed as you guys are feeding my knowledge banks and I'd like that to continue.
regards
Byron

Lownverted

My Feedback: (4)

Your welcome Byron! The Rivets is a great looking plane that I've never gotten around to do. Please, please keep us updated on your progress.

tdstaf

My Feedback: (11)

Thanks and your welcome Byron,and have fun on your project.

Tim

Nitro2Burn

Good news for the project, Charles from CFC Graphics has drawn me up a set of 3 views at 85" span and they are on their way. Hopefully once they arrive I can get started on the fuselage so I can get a plug worthy of making a mould from.
Looks like they are changing the rules slightly over to to incorperate 2 classes in F1 so will have to keep this in mind when making the plug to ensure it can accomodate a tuned pipe for the open class later on.

Can not express my excitement in these drawings, the last scratch build I did anywhere near from nothing was my yr12 HSC (final year of schooling before universtity level of education) woodwork project back in 1992 when I built a semi self designed bipe for a OS61SF 2stroke.

Lownverted

My Feedback: (4)

Any more progress on your Rivets project?

Nitro2Burn

Yup, so I have my wing all done except for the wingtips, I have gone for a foam core with balsa spar lined with carbon rovings and a section in the centre of carbon weave. It has come up a little heavy but still within limits for me. I think some of the wieght is in the undercarriage blocks though since the legs are mounted to the wing not the fuse.
Speaking of fuse I had the plug about half built when I was speaking to a guy at a show who put me onto a place locally that I can get blue foam (kinda hard to find here in Aus) so I have decided to ditch the current plug and start again, hopefully I will grab the foam this saturday.

One part which caused a pause in the process was a change in the rules from 80" minimum wingspan to 35%. Since the Rivets was going to be 40% to make it a bit over 80" I had to wait and see if the new rules were going to be implemented or not. This has happened for all but one race venue which I think will have to either fall into line eventually or fall off the radar. I will try and get a few pics up soon.

I do need to really start pulling my finger out though as it needs to be ready to race by April.