Impulse IF-1

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Red Jensen

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Jan 1, 2018
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90
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Palmdale, CA
Hey all,

Long time lurker. I don't post much but I love this place! I thought I would introduce you to my project. It is my dream to race F-1, this is my effort. I've been at it for a few years, but just now to the point of sharing. I'm currently building tooling, I hope to be building real parts in the coming months.

It will be all hollow molded. Weight, strength and OML fidelity are on the top of my requirements list. I'm familiar with this type of construction from years in the high performance R/C hobby and UAS industry, so this is a comfortable method for me. The fuselage male plug was CNC cut from tooling foam, and joined on a center tube. The tails are hot wire cut 2lb insulation foam, sheeted with balsa and glassed. The whole assembly was body worked and polished, I'm pulling molds from that. The wing and landing gear are being machined direct to mold.

I have a website www.ImpulseIF1.com, if you are interested in following the build, you can search facebook for the Impulse group.

Thanks for indulging me, lots of fantastic information here. If you have any questions, I'm happy to answer.

Cheers
Red Jensen
 

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Victor Bravo

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That's PFC !

Suggestion: if you can afford the weight, look into a bidirectional mixer with full-span camber changing, because you are going to spend 55% of the time in a 2-3G turn, then the rest in a flat run. If you can keep the relative fuselage AoA aligned in both of those regimes, I believe there is a gain to be made. Dave Morss tried this years ago with his "Fast Lane Exit" custom racer, I don't think he got it worked out all the way. But he did have full span drooping ailerons in an attempt to make use of a camber changing wing.
 

Red Jensen

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Joined
Jan 1, 2018
Messages
90
Location
Palmdale, CA
That's PFC !

Suggestion: if you can afford the weight, look into a bidirectional mixer with full-span camber changing, because you are going to spend 55% of the time in a 2-3G turn, then the rest in a flat run. If you can keep the relative fuselage AoA aligned in both of those regimes, I believe there is a gain to be made. Dave Morss tried this years ago with his "Fast Lane Exit" custom racer, I don't think he got it worked out all the way. But he did have full span drooping ailerons in an attempt to make use of a camber changing wing.
This was very carefully considered early on. The reality is that these planes have way too much wing area, they don’t need to generate much lift. The airfoils have been modified and tailored to suit without the weight and complexity of camber changing.
Down the road if it looks like it could be beneficial, having a mold allows another wing to be built without too much fuss.
 

TFF

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Apr 28, 2010
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Memphis, TN
No one is going to complain about the room in the cockpit!

I thought everyone building long wing F-1s figured out the wing area for Reno’s altitude? Hard to believe a top end racer would give up any advantage.

How many you making?
 

fly2kads

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Justin, TX
That looks really good! I am looking forward to seeing your progress. I've always been a fan of v-tails, just because I think they're cool!

I have done some conceptual design work on a sport aircraft based on the Formula Vee racing rules. It looks like we wound up in a similar place as far as airfoil choice goes. Putting the cusp on top really works for this kind of application.
 

Riggerrob

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Sep 9, 2014
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Canada
One less drag producing intersection.

V-tail also has fewer parts to build.
The key is building a few simple parts versus dozens of fiddly bits.
Even if each individual part is light-weight, the weight of all the attachment hardware adds up.

Instead of the complex mixer boxes favored by American designers, you might want to review the all-cable mixing systems used on Russian disco-plane prototypes.

Some of my most recent sketches include asymmetric horizontal tails. A: because they are easier to fold and B: because I have a hard time justifying building two small fiddly bits when one large surface will do the same job.

While your V-tail may be large enough for high speed, this eye-ball engineer wonders if it is big enough for the chaotic airflow during races. Remember what Ladzlo Pazmany said about V-tails still needing the same tail volume as more conventional tails. Can you remember Pazmany's diagram that shows V-tails poking out the corner of the theoretical tail volume "box?"

Prolific small boat-designer Phil Bolger said that there is no point to building a catamaran less than 18 feet long or a trimaran less than 35 feet long. I forget the exact numbers.
 
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Riggerrob

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My Google Fu has not turned up any examples of these all-cable mixers, I'd love to see one if you have an image.

Russian engineer Sukhanov designed at least 3 diskoplans (spelling varies depending upon translation).

www.britishpathe.com/video/discoplan-glider-moscow/query/Russia.
Diskoplan I had the enclosed cockpit suspended completely below the wing. It also had a horizontal trimming surface attached halfway up the vertical fin.

Diskoplan 2 had a bubble canopy protruding above the wings' top skin. The bottom teardrop was barely big enough to streamline the pilot's legs.
The rudder was completely freeflying, like a Fokker Eindecker.
It had a wingspan of 5 meters/16 feet 5 inches.
wing area 20 square meters
weight 240 kilograms
wing-loading 12 kg/square meter
seats 1
It was built by Lavochkin and test flown during the autumn of 1962 by glider expert Vladimir Ivanon.
 

cluttonfred

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Russian engineer Sukhanov designed at least 3 diskoplans (spelling varies depending upon translation).

www.britishpathe.com/video/discoplan-glider-moscow/query/Russia.
Diskoplan I had the enclosed cockpit suspended completely below the wing. It also had a horizontal trimming surface attached halfway up the vertical fin.

Diskoplan 2 had a bubble canopy protruding above the wings' top skin. The bottom teardrop was barely big enough to streamline the pilot's legs.
The rudder was completely freeflying, like a Fokker Eindecker.
It had a wingspan of 5 meters/16 feet 5 inches.
wing area 20 square meters
weight 240 kilograms
wing-loading 12 kg/square meter
seats 1
It was built by Lavochkin and test flown during the autumn of 1962 by glider expert Vladimir Ivanon.

Thanks, Riggerrob, but I was hoping for pics or drawings of the all-cable control mixer.
 

Red Jensen

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Jan 1, 2018
Messages
90
Location
Palmdale, CA
Same. I've found several examples of traditional styles. They all remind me of the old DuBro ones for R/C planes. I wished it were that easy haha. I have a solid design that's adjustable, I was more just curious about the cable types.

Red
 

Red Jensen

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Joined
Jan 1, 2018
Messages
90
Location
Palmdale, CA
Well, the tail molds are now complete. The fuse plug has been rolled on its side and polished prior to molding the left side.
Red
 

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