RC India

Its been a while since I had bought the HK Pulse jet Engine. Its about time I got that in air.

I am undecided here unable to choose between three plans here from outerzone. I am sure Gusty will help in choosing one for me  ;D.

The three plans are

DELTA TOO Wing Span 36"
http://outerzone.co.uk/plan_details.asp?ID=6151

(http://www.outerzone.co.uk/images/thumbs/plans/6151.jpg)(http://outerzone.co.uk/images/thumbs/models/6151.jpg)

LIL TOAD Wing Span 30"
http://outerzone.co.uk/plan_details.asp?ID=5897

(http://www.outerzone.co.uk/images/thumbs/plans/5897.jpg)(http://outerzone.co.uk/images/thumbs/models/5897.jpg)

CLIMAX DELTA Wings Span 40"

http://outerzone.co.uk/plan_details.asp?ID=5875

(http://www.outerzone.co.uk/images/thumbs/plans/5875.jpg)(http://outerzone.co.uk/images/thumbs/models/5875.jpg)

In all the three plans I need to majorly modify the fuse and the nose to facilitate the Pulse jet incorporation as well to to maintain Geometry.
As of now I am leaning more towards Lil Toad  reason being Symetrical aerofoil and I wanted to keep wingspan to under 34".

Gusty your comments are eagerly awaited please.

CLIMAX DELTA Wings Span 40".....

Only for the benefit of uninitiated on Pulse jet
Images

(http://www.hobbyking.com/hobbyking/store/catalog/34247main2.jpg)(http://www.hobbyking.com/hobbyking/store/catalog/34247s2.jpg)(http://www.hobbyking.com/hobbyking/store/catalog/34247s3.jpg)(http://www.hobbyking.com/hobbyking/store/catalog/34247s6.jpg)

Thanks Saurabh Noted. Definitely it looks robust in construction. Anyway I will be reinforcing more.

Wow all the very best sir , its always been a dream to own a pulse jet :)

Thanks Doc.

Sorry sandy

saw it now, will go with lil Toad for three reasons

(a) Sweep back is essentially a design fro super sonic flights, climax has less sweep of them all, she should glide better than the rest, coz it's going to be a engine off landing

(b) Twin fins and the support structure means least spanwise flow and less of tip stall, for the same reason high directional stability, means she will be locked  in on the run

(c) Thicker wing section means (a) High rigidity (b) Nice lift, she can float to super slow landing, not to mention inherent strength she will have

PS
Looks like need to put my pulse jet too to some testing

Subscribed  :salute:

now this is going to be interesting...........   all the very best sundaram sir...

Thanks Sanjay Sir, Gusty, and Jayant.

Gusty let me elaborate on my term of reference and restrictions leading to the dilemma of choice. So you can further ponder over the choices and make a deliberate decision. Further request you to join me with the build if time and Balsa resource permits.

1. High Speed required as you would agree with pulse jet there is an inherent cooling problem if model is not fast enough and further valve pulse frequency does not peak well in low speed. So I am basically looking a very high speed profile.

2. Delta wing has inherent very high wing area. So keeping with requirement of speed I am looking at a max wing span of not more than 34" to keep profile small and less drag.

3.  Static Thrust claimed is about 1.6 Kgs and So I am looking at an final AUW of not more than 1.8 Kgs.  I am looking at achieving this AUW after Balsa Sheeting the complete wing surface and filming it and Lite Ply and Aluminium Taping just under the Pulse jet.

4.  I need to incorporate servo less under carriage fold-able tricycle since I am not looking at a Bungee launch or a ramp launch. So some Ply reinforcements at the under carriage base plate are required.

5.  Which ever wing I have to choose, I have to modify and incorporate a Twin Rudder fin on either side of tail pipe and further elongate the nose of the fuse to incorporate the nose gear, fuel tank and other electronics and to maintain symmetry for better CG.

6.  I have chosen these wings only to adopt the wings ribs profile and construction pattern. So even if I have to choose the Climax Delta I might drop the inner most ribs and reduce the span still from 40" to say 34-36"

As I look at it the three wings have following profile :-

(https://lh3.googleusercontent.com/ePVB8HsaD5bPevJ2J4Lx_5k6LpZ3NBqVyl9cGNPsdFw=w370-h278-no)

To keep speed up my choice is now between a reduced wingspan of Climax delta of 36" or a Lil toad. What say gusty which one should I go ahead with. Very thin chord I might not be able incorporate a fold-able under carriage.  :headscratch: After all the research I am seeing myself back at Lil Toad 😃

Sir,
Anticipated speed 100mph/150fps?
Or more?

Take off ramp a la V2, or dolly, as alternatives to u/c?

When you post the video, i'll surely have the headphones on, to hear the music!

Godspeed on this project.
Regards.

PS:
There is a lesson hidden in your posts for all newbie electric flyers who think the thrust from the motor/prop must exceed the weight!
Your plan to fly a real jet at 90% power to weight ratio is proof of what i've been long propagating on this forum, namely, trainer models can easily fly on 50% power/weight ratio.

Looking forward to build log and video, after video of Papillon, which i suspect will fly like a jet!
Regards.

Thank you very much for the best wishes Iyer Sir.

If it touches 100 mph I will be thrilled for sure sir.

Dolly is definitely a fantastic idea to do. Thanks for that sir. Without UC. It will have huge weight reduction.

I am too hoping a very tight and fast flight envelop for Papillon.

Regards

Iyer Sir with your idea of Dolly, now choice is very clear that it is Climax delta with span reduced to approx 36 inches. Thanks. Will go ahead with that.

Plans for Climax Delta Printed out. It came in about 56 A4 Sheets which when joined will for two A2 Size Plans. one for wings and one for fuse and fittings. Quite a detailed plan I must say. Sheet one with fuse detail is not of much use to me. I will be using only sheet 2 with the details of the wing profile and construction detail.

(https://lh3.googleusercontent.com/d9ReCo7VDrtcP-P380RqwaPaoxjssXCVENvPH-kkqQE=w881-h643-no)(https://lh3.googleusercontent.com/2nTnbpvZv6HOYgxkkK6UfmzEcXNIWdZ0n-1gRw-xO2k=w869-h643-no)(https://lh3.googleusercontent.com/aqpkx4O1k1zpmcpwlsVQIrvF_Q3PO4OQrYOjIzB2GGA=w857-h643-no)

Going to be amazing build , I think . Following :-)

Thanks Aditya

Derived Data from one of the online wing loading calculators posted here. So I am not badly off here with the speculated dimensions of 34" span. Ideally I am seeing I should have kept myself at 30" only. Still no worries.

http://www.flyingsites.co.uk/downloads/wingloadcalc.htm  

(https://lh3.googleusercontent.com/R4C-1hkMcZDcHb5GP3P27rmWI9STdp_B49vQuFUAOD8=w483-h643-no)



PS : Gusty your take on this invited. Correct me if I am very wrong anywhere.

Planned Modification to the Wing Profile and construction is as under.

With the modification to the span and chord length, I need to do a fresh CG calculations though.

(https://lh3.googleusercontent.com/jxAsMoItcISVCck1u1uqI_qHub6UToR-2JnICIl9g5s=w684-h643-no)

Sir,
For a moment i feared that the wing cube loading would get too high due the size reduction.
But with round numbers like 64oz and 4sqft, it is easy to see that the wcl will only be 8.
At 16oz/sqft and wcl 8, shouldn't be hard to handle. (In 60-80mph range, that is)
Wonder how she'll handle at significantly higher speeds.

Curious about where you are planning to mount the motor...
Regards

Sir with Wing dimension changed CG will have to re-estimated again. The Pulse jet is just about 400gms Plus and its heaviest Parts are  the intake valve area and combustion chamber. I will arrive at the rough CG of just the Pulse jet by balancing and will try to keep it slightly ahead of the wing CG spot of wing and then try to balance the wing at CG by adjusting remaining parts and the pulse jet. The Pulse jet will be mounted on Top surface with a gap of 1.5-2" between the combustion chamber and the top heat shielded surface. 2 Degree upthrust of tail pipe will be incorporated.

Wooo this thread is gonna a knowledge overdose with all the geniuses at work ... Enjoying every bit ....

Sir,
Hope you don't mind my pestering you with my curiosity.
The project is too interesting to stop queries!

Will the cockpit and fin be in the way?
Or will you delete cockpit, and replace fin with wingtip fins?
Does tailpipe upthrust mean the same as equivalent downthrust for the airframe?
Does the motor really glow red hot?
Will you use insulation (like asbestos) or reflection (like polished steel/aluminium)?
The 1.6kg thrust is static thrust or at typical (?) flying speed?
Does the thrust increase with speed?
What, in a pulse jet, is the equivalent of prop pitch? How to predict estimated speed?
And finally, is this the first attempt in India, or has someone already 'bin there, done that'?
Regards.

Sir you are most welcome to any number of times. I feel honored  :hatsoff:.

This being a first model for me too, each query is a refresher for me as well.

1.  I am not adopting any of the design & Plan of the "Sheet 1" which is basically the fuselage and how its merged with wing. I am just using the "Sheet 2" the wing only. I will be making a square box nose with sharp tip as indicated in the sketch to keep the fuel tank and electronics. Since its going to be box cross section, it will have more height than the chord thickness of wing but I will taper the rear end above the chord thickness sharp and flush with wing top surface and well before the intake of pulse jet to facilitate easy and good aerodynamic airflow to the valves. I will add some more sketch to elaborate the design planned. There will be no cockpit as such. For ease of construction I am not adopting any of the round nose design as in most delta pulse jets already used by other's in international scene.

2. Cockpit is deleted. Fins will not come in the way at all since the twin fins are going to the wing tips.

3. Yes Sir by the tail pipe upthrust you can say equivalent down thrust for the air-frame as well as a positive incidence for the wing surface.

4.  With sufficient airflow around the Pulse jet it will not heat up at all to red hot. Aim is to prevent that with speed.

5.  I am planning to use Aluminium tape over the ply surface may be two layers. No insulation like asbestos required sir, since wood as such too is a bad conductor. With good airflow nothing should be required.

6.  1.6 KG is static thrust and with gain in speed thrust too will peak. Design of Nozzle is such to increase fuel feed with increase in  air speed entry and air volume. Even the frequency of valve pulse too will peak. Upper thrust limits is limit less and can only be hypothetical.

7.  Theoretically Pulse jets can achieve limitless speeds unlike the props and the limiting factors of pitch of prop and its breaking effect of the airscrew.

8.  Is it a first time in India?? Can't really say but I will be thrilled if its first. Sir you have just motivated me a bit more by that query.  ;D .

Regards

PS : Incidentally Papillon came out to just 10.5 Oz/Sqft.  :giggle: Its a glider too I came to know.

@rcpilotacro,
Gusty sir,
Where are you?
At least 2 guys (Col & me) await your inputs to this thread.

Its a different matter that all Indore flyers are waiting for you...

This professor giri and teaching is taking up a lot of my time.  Had a long chat with sandy. Few pointers one must keep in mind with delta is that.

1. CG with such wing is one very critical aspect. Estimating it is a pain. Sandy tells me there is an app for that. Apps litmus test would be this project

2. Engine mount into the wing would need to be slideable so as to match the cg

3. Heat generated would be high. Some protection would be needed near the tail pipe zone. Though it is not a mandatory requirement coz exhaust velocity sucks in surrounding air which acts as a heat shield

Wing would be better place for rx sandy. I would keep it away from vibration heat and metallic shield and spark

Very interesting sir. Subscribed.

Tiled plan has been joined and it's a huge plan. A0 size literally. What was I thinking  :giggle:

If I don't use the inner most ribs two of them for symmetry then wing span works out to 32" and it's perfect for me as of now.

(https://lh3.googleusercontent.com/4fA4PNnTyEqzM5ANRY5c7SShuqHp44dJdJ9YGAmn1as=w420-h558-no)

Sandy sir, I am sure you have thought about and taken care about it, but still good to flag it up.
I assume your are reducing the fuse build up, thereby also reducing the profile area, are you compensating this by some means? Increase in fin/rudder area perhaps?

Absolutely Captain. It will have twin Rudder fins in the wing tips with increased size to compensate. As such length of pulse jet will also makeup to an extent for the lack of original fuse.

I had taken sufficient care in joining the 20 A4 Sheets of tiled plan. Inspite of that I was not satisfied with the alignment of the final result. It had lot of misalignment at critical parts. So went ahead and printed out the plan in an A0 printer in full size two copies. What I realized was that the original was even bigger than A0 size and I had to reduce to fit inside A0. Effectively now the entire plan has been printed out and the final wings span of reduced size luckily turned out to just 34". Now I don't have to drop two ribs and I can construct as it is as per plan.
(https://lh3.googleusercontent.com/C9qGPvanszEiybsWmkUa2uhWcgS_QY4KDVUHE2dOEOA=w744-h558-no)

I flew this model during my NCC tanure.
It was a speed model(control line)
It was very fun to fly it.
We used O.S. .15 glow engine and 20*10 glass fiber prop.(without nitro)
It covered 10 circle of radius 19m. within 22.45sec.
So very excited to see it flying it with pulse jet.

I doubt it can fly on a 0.15 size engine. This original plan is designed for size 0.46 engine size and recomended engine is 40 size equivalent 2 cycle/ 2 stroke.

Sir,a test run parallel to the build will excite us more,just check the weld on the pulse jet before start.

JK

Yes I have heard some weld giving away on getting red hot. Not a bad idea for parallel test run for few seconds though atleast to get hang of starting blues. Should not be an issue at all since its with latest Nozzle.

Extreme flight of outlaw with Hobbyking pulse jet
www.youtube.com/watch?v=e5wsnnr-JKU

One more flight video by others
www.youtube.com/watch?v=TTc6MmHRlsQ

I bet no NCC unit ever had this model. And C/L? You must be kidding

If I remember right C/L speed was on 35 feet lines. This size model even with 35 feet lines will not be able to pull its own and line weight with 15. Let alone do it in 22 odd seconds

Flyingboxcar then you must visit Jaipur Ncc campus. As i said i flew it with .15 engine and it was a c/L model so it's wing span was 40 cm only.
I'll post pics of that model if i visit that campus again.
Shobhit Sir know's coz he was commanding officer that time.

Hi Antriksh your earlier post was in a way implying that you had flown the very same model in this thread. Wing span of this model is 40" (inches) and which is approximately 1 Mtr/ 101 Cms therefore the clarification by me and Captain.

I am sure you would have flown a 40 Cms wing span delta model with a 0.15 Engine on CL. A 40 Cm model is very much possible with a 0.15 Size engine.  

Using the data provided, ie 19m (say 60ft), and 10 lap time of 22.45sec, we get a speed of 168ft/sec or 182kmph. That sounds correct for a CL speed model.

But 168ft/sec is 10080ft/min. So if the stated prop size (20x10) is in cm, 8"x4", the motor must have been doing over 30,000 rpm!
More likely that the prop was perhaps a 6x8 or so, which an OS .15(FP?) could possibly have turned at over 15,000 rpm on a healthy dose of nitro.

Anyway, good to hear some CL talk...

Wowww! Wowww Wowwww!! ... My fetish for Delta would take a whole new turn! With "Hai-2" Flying wing still 60% Complete on my workbench and Kyten Delta Kit bought from UK still in Closet, I think this Pulse Jet Engine (Poor Man's Turbine Jet for paupers like me) is enough compelling reason for me to jump in.

I am planning to CAD the plan like I did for Hai-2. Sundaram sir, if you have rough sketch for the Engine pylon, do share with me. I would include it in my design and would see if we can incorporate FRC paneling and some heat retardant covering around the Jet.

Do share your tips on the Pulse jet too, as it is a very rare power plant and your experience in tuning it could save laggers like me to save from dead sticks.

Sure Ujjwal will surely be adding more sketches and details and complete experience on tuning and test runs too. Definitely noted to include Engine mouting details too.

Iyer Sir. Its 191.51 Kmph to be precise {[(2*22/7*19m*10laps)/22.45secs]*3600secs}/1000m.

An 8x4 2 blade should achieve it in 11200 RPM says my phone RC Tools app. Is it way of the mark? I have been too dependent on it till now for my static thrust estimation and speed calculations. 

Iyer Sir's air screw analogy applying  Prop pitch 4" 12000 RPM works out to 200 R/Sec which is 800 inches per sec forward travel which is 20.32 mtr/Sec i.e 73.15 Kms/hr. Wonder how the app is calculating double this.

Professor Gusty is desperately needed here.

Iyer Sir my Phone app sure has a bug. Its calculating Correctly in mile per hour accurately  as per our analogy but Kms/hour is way of the mark and in fact is not changing at all with change in pitch of prop only Miles per hour is changing.

Thanks Antriksh for the invite. There is a lot of difference between a 40cm model and this one. Not all delta's are same

Iyer sir,
an OS 15, without any nitro on a 8x4 (coarse pitch) prop doing 190 Km/h is something hard for me to digest.   
Even on a 6x8 the stock OS will not do 15k on rpm
BTW The current ratified FAI F2A record is 307.4 K,/h per the FAI site

Also you cant literally go by the pitch of the prop !  Little bit of prop theory is here, and in the thread (http://www.rcindia.org/rc-general-topics/basic-aerodynamics-for-rc-flying/msg233144/#msg233144)

If pitch of a prop is said to be 4", it will give you that forward pull only in a zero drag condition (i.e without being attached to a aeroplane or an engine :) ) this is called GMP. PP (Practical Pitch is always less and it depends on (a) Aeroplane design (b) Speed at which it is travelling. Higher Pitch props unload at high speed and peaks on speed performance at its optimum speed, above and below it that prop under-performs

Any 4" prop will not give a PP of over 3.2" nothing more

Yeah Sandy ! software has a bug, not your phone

Logical question would be what happens to a 3 bladed or 2x3 bladed contra prop ?

I am not going to answer that, let us throw this question open for discussion

Thanks Gusty. Now when its ratified by gusty we are definitely reassured.  ;D

This one below is specially for Ujjwal Jhon . Wonder how they managed to fly four of them together with same colour scheme in same pattern and at such speeds.  {:)} {:)}

www.youtube.com/watch?v=ldgmKdfKGZA

PS : Now its high time I stopped jabbing away on the key board and start building some.

Yes you are correct Sundaram Sir.
I always like to share my little experience.

Wooooaaaa!! That was like Monaco F1 race!! Cant believe !! jaw dropping !!

So should I pick up Climax for CADding (sadly its PDF is raster - DFX conversion would be hell). We can build multiple copies once CADed.

Ujjwal not much to CAD in this plan of Climax delta. Only ribs are available and if you are constructing fuse as such then the firewalls are available. Rest you might have to plot every other part all afresh by physical measurement from the plan. The sheeting's, Side walls, Transom pieces, top and bottom braces of the wings, wing leading and trailing edges, control surfaces. Further to remove the pixels of grains pattern of balsa in every part is going to be a nightmare for DFX Conversion. Conversion to a DFX would be a project in itself. You can try that surely

For me building a single model scratch building is a much better option. as such the plan parts are very conducive for that. My main reason for picking up these plans was primarily because the plans were Conducive and flexible to even rearrange the inter-say distance of the ribs on a grid board.

Some progress.

Two sets of Ribs are out from the plan for cutting.

(https://lh3.googleusercontent.com/cSjRwJvqa-B7hCU-qqZLcseHGUwxG3FjBSG7bLH6UgmaKhmpn34TIlYcS7XW2ehPS9dW0lr_gCkqaFnc12RFBjnwQ73mA7wy4-CVsRWahJIrdCRx2w-HswtHjuKggam6y3W98WwuyKeuidA_yTfUbS9olMkD2u5x2Ylri1jrPNv0xj-LOjKV1AVsv2-otJRTGh9L2AMpGabunjf0BgaRQ1SwOLkt-BaR9p6uXqjdUApYvETIDUEXBb-hf6MB7vsVOSJ59Jd3ZPuzo5WbiBIE_EX2RPCybgQiyactqXvqZ34j_rTNmX40Br6moJki53qLaeiuMc52izn50RzLzxVoZyVVdCzXbNpeokkZFpNsN8k8gEuwE-Y6KE5QVHmjxYnQXZwRP-Rgn5tJeC0fx7ojiXVjUqHYks_LzKSoNqt877e4ZUyedKD8lPsKkkxveb0uiZ-MWH6_WAR2ZeL-MuY0rN3UjOVxu6YyUGrmBqi6mEUxDt9v_JFkNmgq_061guA3mIH_QA=w858-h643-no)(https://lh3.googleusercontent.com/LuoMRkNYd89uoz5mq2HdyxK9W-KsVGGbSCr3u0vQoqSTYQ1sHfAIov0O6mFBWppTTIF53d6yqVVd07hhyldXXymMgs2F99kMPbfbc64gVbeZYh_ZFJCrEAY80ZjhlEit7gCLmQDbGZWevCa_pxbuEPWWqEm0wSdxKAL6sKpMQ3M7FFMtwq2pz0Y8FMr543p7tMil1yoJmtQlXL7upgQWtV59Jth_77tx_BMjWzEO-JB8zibcrfCcH5CtxcWEqzhEqT5C8FWP39fY1bKsIOA-Qigln_b5QX8jS1_YYunjFeXnFq3bVO1uRBGe_R82Mpkr0YcpSAks_odOxpPrNHnTeX54KPyMkC-Gbzt2FcddqFMA2mfMifitx6A13oDen8rJOHAX0UymOHRqmL00485X-nzhGc1-Jx-GPPvrxNL0xqeewkp1AZ-WIxvdfJGRLekiAb0-LkZgFlJWfD0ZYippukyxinx3Z4z8gg9n6oGMCoMEo_ontN7mRiiN0X9Q_4yFcChazg=w858-h643-no)


 

Wow !! thats some progress. Sadly I am more on the Tech side than arts side and weariy of cutting plan by hand like old school vetreant like you (specially Ply parts). I agree the CAD conversion of Raster planes like that is not like cakewalk I had with Vector PDF files. Will give a try in DevWing/DevFus.

All the best for the build

Why do you need to cut two sets of rib templates, half the numbers would have done and you could have kept half on the plan to build on.
Or instead of cutting up your plan, just place your plan on the balsa sheet so that the inked side is on balsa and iron over with warm iron to get nice black lines of the profile you want to cut 

Thanks Captain for the tips. Yes nice idea on iron on ink transfer. Will try that.  thought of using a carbon paper transfer though. I am a newbie on Balsa build need to learn a lot from maestro's. I was just going to make an economic arrangement on the balsa sheet with minimal two sided tape and just cut it. With resources at disposal getting one more A0 sheet printed is no issue.

Anyway I have retained intact the portion of plan required to be build on.

Came across one more guy who had built a similar model for HK Pulse jet.

(https://scontent-lhr3-1.xx.fbcdn.net/hphotos-xpf1/v/t1.0-9/p180x540/11903975_10153616907377450_675549772330009466_n.jpg?oh=af4848dba5cf943c55006bc1ebf63b1d&oe=5682AE8D)

Thank God someone bumped this thread. I had almost gone into hybernation on Aeromodelling. Reached Coimbatore safely settled down. Param busy in 11th 12th. I am busy doing a PG in Mass media communication and Journalism.

College grounds is an amazing place to fly in the foothills of Neelgiris. Need to pickup back where I left it.