Switchblade update

[R&R Model Aircraft]

All,

Since I have been asked, here are some photos from a launch last week of prototype # 3 which is very promising. I had 2 1/2 flights :blush:

The first was very nice (the one in the photos) , F12-5 cut down delay to F12-3, with a bit of a CG problem due to an oversight of using the parts of the aerotech case (24mm) and the nozzle, liner, cap and thinking that was ok. It appears that I needed an actual used motor as their is fair amount of residue after burnout. This caused a bit of porpoising at first, but was brought under control with a bit of down elevator and flew with a smooth glide which I promptly landed into my friend's leg just before touchdown.:y: The wing sheared cleanly and was repaired shortly after. This is why I now have TWO prototypes of my model.

The second flight (first of the second prototype) first had a bit of trouble igniting, then promptly blew out the nozzle and end of the case (Aerotech F12). On to case # 2 (sigh). Since the first seemed a bit early on ejection, I went for the "full" 5 second delay - did I mention this was an Aerotech motor? - I was treated to a "bonus" delay that went after about 8 seconds (the model was already sticking in the ground by this time). It is very repairable and both models have taught me likely failure points and where to improve on the future kit.

I will have the two models at NSL and will fly (weather permitting). Suggestions are always welcome.

Thanks,

David

BTW: These photos are taken by Jim DePape who also got some stunning shots of my Gamma and Delta Stars during NSL 2012 this past weekend!

 

[aerostadt]

This model looks terrific. I wondering about the size like wingspan and fuselage length. It looks like the wing tips fold down on take-off. Your pivot mechanism looks interesting. Any details? I found the 24mm AT F39 reload to be very generous on delay time. I was always shorten it.

 

[WillMarchant]

Thanks for the update, David! Looking forward to getting one of these kits...

 

[mr_matt_II]

Wow David what a lot of ups and downs!! Great looking design!

 

[R&R Model Aircraft]

Wow David what a lot of ups and downs!! Great looking design!

Unfortunately, many of the "ups and downs" are my fault

It will be flown by my friend (and far better pilot) at NSL so I can observe and also get his impressions. It is taking longer to develop than I had anticipated (it is amazing how a job and family life get in the way of the important stuff :wink, but I would hate to sell a model that wasn't as good as I could make it. Being a builder, there is nothing worse than when I am on the receiving end of such. I keep asking "why didn't the designer do this?", realizing of course how hard it is to make any model design, let alone finding all the potholes.

Best thing I can hope for is someone thinking they got their money's worth. Like most of these things, people do it because they want to make models and share them with others ( and lets face it, nobody - not even Estes- gets rich off model rockets (as far as I know))

David

 

[ttabbal]

I want this....

Any idea on target price for the kit? ETA?

 

[R&R Model Aircraft]

I want this....

Any idea on target price for the kit? ETA?

I had to change the design after flying it at NSL. It flew beautiful, but I found a few construction shortfalls ( A bit too complex for beginners). My plan is to have a beta kit available at the end of July for a few people / testers to find any bugs (sorry, they are already chosen ) Full production as soon as I get feedback. The important part is that I am really pleased with the flight characteristics. Cost will be based on cost of laser cutting.

Note that the concern for the nose cone is no longer a problem ( unable to find) as the change in design fixes this.

David

 

[ttabbal]

sounds good. gives me time to get my r/c skills up. I've been flying electrics partly to get a good idea how to fly before trying rocket gliders. It's great fun and I'm looking forward to combining rocketry and r/c.

What's the control setup? Ailerons or rudder/elevator?

 

[R&R Model Aircraft]

What's the control setup? Ailerons or rudder/elevator?

Elevator / rudder. Ailerons are not really needed, plus they would be a pain to put in a pivoting wing!

 

[ttabbal]

Elevator / rudder. Ailerons are not really needed, plus they would be a pain to put in a pivoting wing!

I agree they would be a pain to have in that type of wing.

Good luck on the beta test. Please post updates when you have them. I'm really excited about this kit. I like the other ones one your site too, but this looks like a perfect first R/C boost glider.

 

[WillMarchant]

Yup, barely containing my excitement for this kit! It looks perfect for a club build session...

 

[R&R Model Aircraft]

Yup, barely containing my excitement for this kit! It looks perfect for a club build session...

:y: No pressure.....

 

[kjohnson]

Heck, I just want one for myself.

kj

 

[R&R Model Aircraft]

All,

More on the design changes. After seeing the variability on the engine delays (Aerotech has variable engine delays??!! - No way!), the new version will have a servo released main wing. So, it will be a two channel controlled model, but needs a third to release the wing. I found that this will make everything easier and more reliable in the long run. Nothing worse than seeing a model come in with the wing still folded up :eyepop:

This will also open it up to more engine possibilities including Cesaroni motors (3 grain 24mm, etc.)

Construction will be a lot more like the Delta and Gamma models, but will still keep the current shape / profile.

More as I get closer...

David

 

[WillMarchant]

Sounds good! Some people use an extreme motion of an empennage surface to unlock the wing. But a third servo might prevent accidental deployment..

 

[iter]

Servos are both cheap and light these days. I like this approach. The pilot is in control of the flight anyway, he might as well choose when his control begins.

Ari.

 

[R&R Model Aircraft]

Sounds good! Some people use an extreme motion of an empennage surface to unlock the wing. But a third servo might prevent accidental deployment..

Hate this for the reason stated As already said, servos are cheap and that is what I went with. The servos are now all on the inside of the model (no control rods and servos in the slipstream). I am tweaking a few more things with some input from knowledgeable individuals and hope to cut the beta kits in a week or so. Then on to building one for the photo shoot and test.

Of course, the wife may have some things around the house for me to do in this time as well :wink:

David

 

[ttabbal]

So... Can we buy them yet?

Servo release for the wing sounds good to me. I have a receiver ready to go for it....

Any recommendations on servos? I thought I would order some with my next rc order.

 

[Reddwarf]

THAT is cool!

 

[tightwad]

Nice design, just keep us in the loop.

 

[R&R Model Aircraft]

Sorry it has been so long, guys! Man, the summer went fast.

Ok, I finally got a pair of Beta kits cut and I am really happy with it. I also had to increase the wing cord (hat tip to John Boren). I put the new wing (still a flat bottom airfoil) on one of the earlier prototypes and its glide slope was very much improved. I am currently writing the instructions and making sure that a person new to airplane construction can build this. With that in mind, I have to put basics into the instructions such as building board (the fuse is over 40" long!), how to align and balance for flight, etc.

The servos are now on the inside and I hope to post some photos in the next couple weeks.

Also, for those that are interested and notify me by e-mail (David@randrmodelaircraft), there is a limited time pre-Christmas sale on the Delta and Gamma Star kits (current stock is a half dozen each). Mention this and I will take 15% off the price of the kit up until Nov 8th (shipping will still be the same, sorry!). This is NOT posted on the website. This is for people that have been interested in these kits and follow the Rocket Boosted Gliders forum. (to any moderator, please let me know if I am not allowed to do this here - I was not sure)

Thanks!

David

 

[WillMarchant]

Woo hoo! Great news, David, thanks!

 

[ttabbal]

Excellent news!

gimme....

Hopefully I can get one to build over the winter. Is it set up for just 24mm or could one use the 29mm hobby case? I was thinking the F22 might be a nice load... or even the RC case, G12-RC?

Probably too tail heavy though if it's set up for the 24mm loads. Looking forward to it.

 

[R&R Model Aircraft]

It is setup for the 24mm motors. It should also work with the new 3 grain Cesaroni motors. The 29mm motors will definitely make this too tail heavy.

If this flies well, it would be easy to upscale I think

David

 

[ttabbal]

It is setup for the 24mm motors. It should also work with the new 3 grain Cesaroni motors. The 29mm motors will definitely make this too tail heavy.

If this flies well, it would be easy to upscale I think

David

Thanks for the info. I'm very interested. When can I buy one again?

I had forgotten about the Cesaroni 24mm motors... I might have to look into those, one can never have too many motors. Unless you ask my wife. :lol:

 

[iter]

Good job David! I'd like to see more RCRG kits on the market. I like where you're going with it.

Ari.

 

[R&R Model Aircraft]

Main problem with RCRG kits, is the very limited market. I love them, but stocking them is hard in that your money is tied up for quite a while in stock. I have three more designs waiting in the wings that are very different (and pretty cool - and not so mechanically challenging for me to get right ), but doing the switchblade has taken a bit of time as it has enlarged over time (physically). I also don't like selling anything that I am not really proud of as my name goes on the outside.

I would actually like to see a few plans be made available from some of the neat ideas I have seen on this forum.

David

David

 

[iter]

Well I don't have any plans available beyond the basic dimensions, but I'm happy to help anyone who wants to reproduce my work, either in single units or as a kit. I realize that Vulcan is even more niche than most RCRGs, but if anyone wants to make a kit of it, the photo documentation of my build is there for the taking.

Ari.

 

[R&R Model Aircraft]

Ok, guys. Here is protoype 4 / pre- production model. It's weight is 481 grams / 16.95 oz without motor (assume an F-12 /24). This is 2oz lighter than the earlier version. The fuse is now sheet balsa with the servos inside and a wing release servo (three channel). I hope to test fly it over Christmas break (it is done). Now for the issues. There is a lot of laser cutting, so the model will take about as long as a Gamma Star or Delta Star to construct. This also means the price will be in that range as well (about $120.00).

Take a look at the pictures and let me know if this is something you guys would be interested in as I don't want to put the work into the manual / kitting it if I have missed my market.

 

[WillMarchant]

How long does it take to build? I'll probably buy one. But this had sounded like it might be a fairly quick build suitable for an intro class.