rpz-RCU

Hi there guys!

I just received my Patriot kit, and am going through it for modifications. I plan of building it to handle 175mph, so I thought I'd ask for some input on build techniques. Some ideas I have already are:
- Retracts to be Robart air on 3/16" legs
- Gear doors, the front one doubling as an air brake because we only have a 300' runway
- No side air intake scoops
- Rear exhaust, front carb engine
- Jett 60 engine
- Engine mounted upright, pipe through the firewall and exiting below the canopy deck on the side of the fuse
- 1.75" wheels
- Robart pin hinges throughout
- separately controlled ailerons 2/3 of original length
- inboard slotted flaps
- fuel container moved back almost over wing

Anything else I should consider? How about using the tutorial article in the Jet forum for sealing the control surfaces - wing, stab and fin?

Cheers!

Dustflyer

My Feedback: (13)

The Patriot is cool isn't it? A fast airplane with landing gear.. what a concept. Too bad it's a collector's item already. Listed as discontinued on Tower Hobbies site. You are darn lucky to have one. Wish I had bought two!

All that stuff sounds great. Just remember the F-4 concept: Enough horsepower and even a brick will fly!

Am putting the same Jett 60 on mine. 13 oz and 15.5 to 16 on a 10X8. (Get yourself a pile of KB1L's and some Magnum 15 dude, trust me on this one!) Only one thing better: the Bob Holmes special... a Jett 90. Might just do that before it's over. What the heck, you only live once, right?

Here's my plan: Jett 60L FIRE for now, quiet pipe on the side, forget the fake intakes, B&D retracts, extra CA hinges, 4-40 rods all around. Flaps? Not a bad ideal but too much work for me (I'm a lazy SOB, rather fly than build!); coreless Futaba servos. I think it'll work.

A clipped wing "Mini Dust", a Patriot, a HotSpot. About as good as it gets....

rpz-RCU

Actually... One thing I forgot to mention - Don't know how...

I'm thinking of actually fitting the tail cone with a rocket engine clamp. I figure that a 'C' size engine with a 2 to 3 second burn is all it needs to turn more heads and punch the bird to supersonic... any longer and it'll likely be acellerating too fast, over rev the engine or something...

Has anyone tried this? Is it legal? It is still controlled, and I do have 8 channels on my JR 8103 Tx and Rx to play with... Ailerons, throttle, elevator, rudder, flaps, gear, Gyro remote gain and rocket ignition. By the way, the Gyro is for the rudder/nose wheel control when on the ground... From what I have seen and heard, the Pat is a bit of a bear on the takeoff roll.

3...2...1...Afterburners!!!

Razor-RCU

My Feedback: (50)

That would balance her out with the Jett on the nose-

Does sound like a fire hazard tho-

The flaps are a good idea with your powerplant in mind, and a 300' strip...

Mine lands at about 10-15MPH with split flaps-

Rudeboy

Hehe... the rocket engine thing sounds cool... and will most certainly turn some heads.
I don't think over revving the engine will be an issue. Jett's are a pretty sturdy piece of equipment.

But... how much thrust does such an engine produce (the rocket I mean)?
Are there data somewhere on the net about these things?
You will need a fair amount of thrust to significantly increase the speed of your plane.

charles w premo

I had a patriot with a Estes D in the tail end I used a 9 volt Nike battery and a micro servo to fire the engine. I usually used the rocket engine on take off. It was a sight to see. I would start to rotate after 50 feet and the climb out was awesome! They make special engines for glider use I think they are D11P's The reason for this is no exhaust gases go forward. I sealed the forward engine mount bulk head and used some D-12-0 boosters I had. the rocket motor weighs a couple of ozs so make sure your CG doesn't get to far back. After the engine fires you notice a shift in CG.

Rudeboy

Ok...

I did some searching on the web... and what I expected turns out to be true:

You will need a lot more than a "C" class engine to give your 8 or 9 pound Patriot a significant boost... C-class engines produce thrust numbers in the order of 5 or 6 Newtons... that's about 1.3 pounds of extra thrust... and only for a few tenths of seconds...
The only thing you will see with such an engine strapped to the back of your Patriot is a few seconds of smoke trail...

First: You need an engine without a delay charge and an explosive charge for the recovery chute...
The "plugged" engines (for R/C and glider use) seem to be the best choice.

Second: You should be looking for a really slow burning engine... it has to burn longer than 1.5 seconds to accelerate your "heavy" airplane (compared to them very light weight rockets)

Third: you should be looking at a least an E or an F class engine, and it should be an engine that gives "smooth" power.
You don't want 0.5 seconds of very high thrust and then 2 seconds of very mediocre power... you need constant power...

Example: an E15 engine will give you little over 3 pounds of average thrust for a duration of 2.60 seconds. I think something like this might have a "visible" effect on the speed of your plane... but you want even come near to "punching a hole in the sound barrier".
Note the word average in the previous sentence: these engine have a very high thrust when you ignite them but only for a very short time, after that thrust drops dramatically...

To put it short: look for BIG rocket engines...(there are people out there reaching heights over 10000 ft with their rockets...now these engines should get you somewhere... )

Take a look at Aerotech rocket engines , they have high power reloadable engines, but these things cost quite a bit, and you will need a special permit to use or even obtain them...

rpz-RCU

Heh Heh Heh...

I thought I was going to eat some serious crow for mentioning this at all here! Actually, I was thinking that the D engine class with plug or a blast proof firewall would be the ticket. I will look into the E size - That's a lot of wallop!! I have been using multi-stage rockets in the past and am familiar with the operation and thrust numbers. Given eflux celocity at the nozel is in excess of mach, the factg that the plane may already be moving at 150mph should have some but not too much effect on the overall acelleration capabilities of the plane, and it is will not be fighting gravity - likely only straight and level. A longer burn is definitely required if anything more than a short kick and a puff of smoke are to be seen. The idea with this plane is to be faster than the jet jocks at the club, possibly even the region - and to do it in style!

We were out today, and the current speed champion actually went faster than he has previously - maybe 140-160??? rough guess with no equipment to measure today.

Question - will weight really affect the top end speed? or is it only on takeoff/landing where it makes a difference? The chord of the wing is not changing, but the wing loading is. Will a half pound or even an ounce make that much difference? I'm thinking I should REALLY concentrate on smooth lines. How about sharpening the stock leading edges? Will that help?

Thanks for the comments so far!

Hey Sparkplug.... I'm comin' to get ya! :devious:

Razor-RCU

My Feedback: (50)

If your Patriot ends up weighing 8-9 pounds then you should be very concerned-

A little weight will not be that noticeable....

This reminds me of "Fat Albert" the C-130 that has a jet assisted take-off for the Blue Angels-

Thinning out the leading edge huh... Should help (??)

Keep us posted,
james

charles w premo

If you really want to move use the areotech 40-120 RMS (reloadable motor system) with a g33 reload it uses black jack low thrust propellant and burns for 3 seconds and produces an average thrust of 7.4 LBS. and has a total impulse thrust of 22.5 LBS/second which translates to over 3 seconds of over 7 LBS. thrust the propellant weights around 2.5 ozs . so cg is critical. if you put the engine in the tail. all the E and lower motors like the D I used are great for inital climb out but they can't pack the KO punch of that aerotech. It has a 29mm diameter case so you probably can get it to fit in the tail

Rudeboy

Well, actually I have no idea what a Jett FIRE .60 powered Patriot with all the trimmings will weight eventually.... all I was trying to say is that you need more than a few ounces of rocket engine thrust to give that plane a noticeable boost...
Although you might more quickly see the difference on take off. But when the plane is already travelling at "top speed" you need a lot of power to make it go even faster... at least a few pounds worth of thrust.

sparkplug

Wholly Cow RPZ!!!!!

I know you want to beat me but man a rocket I think your going to have to bring some extra underwear for the older guys at the field.

If this continues your going to force me to get a new jet plane. Theirs only so much I can do with my current jet to get more speed out of it. I like the idea of reducing the outlet by 1/2" to increase the velocity at a decrease in thrust. I already have a very short take off so I can suffer a longer roll for more speed.

With all this talk about the patriot I am starting to get an itch for a patriot as well. It's a nice inexpensive alternative to jets and you can still get them to go fairly fast or we shall soon see

Enjoy!

Rubbie

You will have to read the MAAC rules (if you plan on flying at a MAAC field) I think is says that pyrotechnics (rockets) are not allowed on planes with internal combustion engines. A guy at my club put one in his Patriot a couple of years ago and it was really cool seeing his plane explode in mid air when the rocket misfired.

Don't get me wrong I think it would be cool to see, just double check the wording at the MAAC website.

MajorTomski

Ummm Err, I don't think you need to stress out over having the nose gear door function as a speed brake, I routinely flew my .46 powered patriot off a 250' paved runway without over running the end. And why waste the weight and complexity of going for slotted flaps when a simple flap hinged on the bottom surface of the wing will have virtually the same effect?

rpz-RCU

Hmmm... Rubbie you bring up a good point. I will check out the details of the restrictions. No sense doing something stupid even if it is fun. Stay tuned for an interpretation.

The gear doors are actually more important at top speed than as brakes, I believe. The main difference between the implementation of the slotted flaps and the standard flaps is basically the positioning of the hinges. Unlike the more complex implementation on full scale airplanes, the model implementation I am thinking about is actually closer to the hinged type than the "true" slotted, but more lift is generated with less drag than standard flaps.

Truth be told, the real reason I am going for the slotted flaps, gear doors, etc. is more for the overall "wow" factor. Our club needs a little motivation from time to time...

After all, this hobby is supposed to be fun right??

rpz-RCU

Ok... I just checked on MAAC, and this isall I found:

"Pyrotechnic and explosive devices are not recommended to be carried or activated by model
aircraft."

and

"Internally mounted pulsejets, rocket or thrust engines are not recommended because of the
danger of fire."

My interpertation of this is that a commercially available rocket engine is not considered a pyrotechnic device - it is in fact a motor, and is used in some cases as a launch mechanism for gliders. It does not explode, nor is it used to produce spectacular displays of fire and such.

I have launched a lot of rockets in my day - single and multi stage. I have never seen a properly build rocket mount blow apart. This stipulation is a recommendation, and like most things in the hobby, common sense goes a long way.

charles w premo

Rocket engines are like fire works in NY state They are only illegal if they catch you I also fly ducted fans and a good 40 size speed plane like the patriot or the f-20 is a whole lot cheaper to run then my ducted fans. I put a yellow f-16 in the ground last week end and all I saved was 3 servo's . I could have bought and out fitted 4 patriots for the cost of that 1 jet. I guess I'm a glutton for punishment cause I just sent for a BVM maverick.

mpriestley

My Feedback: (1)

I know this thread is a bit stale but...

I am also putting a rocket system on my Patriot (something I thought was an original Idea<lol> but,..)

I was hoping for a bit of advise.

Ie. incidence of the rocket engine. I have done my best to have the rocket perfectly parallel to the horizontal stab. is this the best way to do it or do I need to be overly concerned?

I am using an E rocket with no explosive.

how about the balance, should I balance with a loaded rocket or a spent rocket?

Any other advise is greatly appreciated.

Thank you,

Mike,

RPZ

Well, the thread may be stale, but it just so happens that I am currently in the process of installing the rocket mount (yes - I don't get a lot of time to build...). As best I can figure, the thrust line of the rocket should be in line with the thrust line of the engine. I think that the Patriot engine is installed with a 0 degree offset on the firewall, so I am aiming the motor straight out the tail. As far as weight and balance is concerned, I am putting a Sport Jett .90 on the nose - I need all the weight in the tail that I can get. Combine that with a 12oz tank, with a 2 oz hopper (main tank is over forward section of the wing, hopper is just over the retract, right behind the engine), the weight onthe end should be OK. Keep in mind that a tail-heavy plane is more difficult to handle and a nose heavy plane lands faster - I am opting for a balance with a loaded motor near the rear of the CofG range, spent/empty motor in the front or ahead of the CofG. I am also using a JR8303 Tx, so when I flip the switch combination (three things need to be in place for the rocket to fire), I will also set up the elevator to compensate for a spent rocket. That means that the natural tendancy once ignited will be for the airplane to nose up. Not a bad idea once the candle is lit.

In Canada, I can only legally acquire D size motors, so I will only get a visual impact of smoke and a little kick in the pants - at the top end it will actually have more effect than at the low end, as the plane will already have forward momentum. Also, as I said, there are three conditions that have to be met for the motor to be lit - I figured the last thing I wanted was to hit the wrong switc on the ground or during a hairy landing and inadvertently light the candle!!! The ignition conditions are:

1) Gear must be in the retracted position - this means there is no option for a "ground light" or a "JATO" style take-off. This is for safety only. I have lots of paved runway, so I don't care about takeoff distance. Also, on a hot summer day, a JATO launch is a great way to light your field on fire!!

2) Flaps must be retracted - I have separate flaps and ailerons. I figure that with the all-up weight of the airplane, the landings will be hot, and I needed to slow down the plane without stalling. Also, when the flaps are down (60 degrees), the plane better be going slow, so this would be a BAD time to ignite. In order to accomplish this, I have a switch on the transmitter that is used to set up landing configuration. This is a three-position switch. In the center, operations are normal. In landing, flaps are deployed. In "Elevator", there is a slight nose up programmed in and the gear servo advances 1/8 of a turn closer to the contact point.

3) MIX must be ON. This is only a special function switch and is huge on the 8303. This switch further advances the gear servo by an additional 1/8 turn.

So, to fire the rocket, it has to be loaded and armed (ignitor connected to the main battery via terminals in the tail - by the way, the 4.8V system battery is sufficient to light an igniter). The gear has to be up, MIX has to be ON and I have to select Elevator mode from the configuration switch, confirming flaps are retracted.

I can't wait to see it go. I will actually update this thread once the plane is finished and flying to show a MPEG of the ignition sequence.

If you could show any pics and the results of lighting that E engine, I'd love to see it!!

mpriestley

My Feedback: (1)

I will definately post my results.

I just finished the instalation of the rocket mount/tube and the electrical system that goes with it. I used a separate 9volt battery system for the ignition system.

I think it is going to be a real kick in the pants and it may not really give the plane much kick but it should be a lot of fun watching the fire and smoke.

I think the JATO take off could be really cool also.

I have a c-160 that may get some small rockets attached is this is successful.

keep me posted and Vice Versa!

good luck.

Balsa Master

erm... theres a post under sailplanes about rocket gliders, read my response to the legality question, you may not like what you read.






hate to brak it to you all, but a c isnt even going to budge it. theres more friction in the wheel colalrs under the weight of plane than that c's gonna help you. you will need more like a E whitch i dont recomend since your gonna probably shoot a E engine into the back of your FW.now, if you wanted somthing to look cool, appoge makes these little tiny thin B motors 10 mm you could make little pods under wings and put maybe 4 of em under each wing and THAT would look cool. and that adds up to a mid d engine with 4 under each wing.you will need to fiberglass behind the engines so the thrust doesent furn the wing. (although thats a fast way to get your cliped wing :-)

also recomend a tilt switch (mercury switch) so that the engines wont light in a dive by accident.

pic below, engines wont light till plane is at 15+ degrees and the connection has been made by the servo.

gotta love that concord look to it. and its going to be more stable power since it will be closer to CG and CP then at the very back.

Razor-RCU

My Feedback: (50)

No matter what happens with these Patriots I sure can appreciate the mods y'all are doing- (Another Jett-90 powered Patriot? Awesome...)

Just do it safely, and get pics or video

Goinstraightup

My Feedback: (26)

I am eager to hear and see the results too. My F-15 was pretty underpowered with an OS46SF. Even with the UT muffler it wasn't super fast. I always thought about some means of extra power . I augured it into a warehouse on its 54th flight so I never found out. I have a patriot ARF. The radio and engine are out of it now. I also thought it could have used more power than the UT OS.46SF.

Jeff

scottrc

Man, my Patriot was fast with just a OS 46SF, MAC tuned pipe and header, and retracts. Your's are going to be balistic. You can't ask for a more stable, high speed platform to experiement with. Great Planes really did an injustice to us by discontinuing the kit.

Good luck and I can't wait to see the results. i wish I had the time to experiment with you guys.

Scott

AeroD79

My Feedback: (2)

thinner LE leads to nastier stall characteristics especially with swept wings in place.


id say keep it simple...unless you want it to fly like a full brick