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Everything Radial Engines

Old 08-01-2010, 12:48 PM
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Default RE: Everything Radial Engines


ORIGINAL: 77chickenhawk

can you make a engine like this in a 200 to 240 mm diameter? in either 7 or 9 cylinder configuration?
no one makes a engine like that.. im sure if someone did. they would be a hot selling engine. i would have one for every WWII warbird that came with a radial...If the price was rite...


<span style="font-size: x-small"><span class="short_text" id="result_box"><span title="" xc="not the minimum possible diameter is 270mm to 7 cylinders" wc="non il minimo diametro possibile &egrave; 270mm a 7 cilindri" closure_uid_gfh3a7="63" style="color: #000; background-color: #e6ecf9">not the minimum possible diameter is 270mm to 7 cylinders</span></span></span>
Old 08-01-2010, 12:51 PM
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Default RE: Everything Radial Engines


ORIGINAL: Cybertom

Radial77,

Looking at the 3D drawings it makes me wonder if the mechanical fuel pump is serving dual purposes. In addition to providing a pulse it may also act as a turbulator.


If you read some of the projects conducted by Heilmann Radial Engines theory doesn't alway match up with reality and sometimes you just get lucky. Use Yahoo Babel Fsh or some translation software to translate this webpage:
[link=http://www.heilemann-sternmotoren.de/index.php?option=com_content&amp;task=view&amp;id= 70&amp;Itemid=87]Heilmann Radial Engines - Radial Flow Compressor Project[/link]

<span class="long_text" id="result_box"><span title="" xc="The engine crankcase always aspiring big problems because they create imbalances and gaps during aspiration, which is why this mountain turbine rotanti.Ma changes in weight and more effort for the engine" wc="I motori che aspirano dal carter hanno sempre grossi problemi perch&egrave; si creano scompensi e vuoti durante l'aspirazione, ecco perch&egrave; montano delle turbine rotanti.Ma questo si trasforma in peso e sforzo in pi&ugrave; per il motore" closure_uid_qcqwt3="570" style="color: #000; background-color: #e6ecf9">The engine crankcase always aspiring big problems because they create imbalances and gaps during aspiration, which is why this mountain turbine rotanti.Ma changes in weight and more effort for the engine</span></span>
Old 08-02-2010, 03:58 AM
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Default RE: Everything Radial Engines


ORIGINAL: Cybertom

Radial77,

Looking at the 3D drawings it makes me wonder if the mechanical fuel pump is serving dual purposes. In addition to providing a pulse it may also act as a turbulator.


If you read some of the projects conducted by Heilmann Radial Engines theory doesn't alway match up with reality and sometimes you just get lucky. Use Yahoo Babel Fsh or some translation software to translate this webpage:
[link=http://www.heilemann-sternmotoren.de/index.php?option=com_content&amp;task=view&amp;id= 70&amp;Itemid=87]Heilmann Radial Engines - Radial Flow Compressor Project[/link]

Thanks for the link cybertom. Had it translated although the english version from google translate leaves much to be desired. Btw, not really sure what I'm looking at. Looks like a centrigugal type impeller unlike the design incorporated by robart and OS. Not too sure but wuldn't the velocities of the fuel/air mixture be too great for a normally aspired engine. The heilemann setup may actually accelarate the mixture too quickly and the intake is placed right next to this high speed mixture. Would this actually cause the engine to stutter at high rpm's. Was this ever incorporated into heilemanns 9 cylindr radial?

R77
Old 08-02-2010, 03:31 PM
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Default RE: Everything Radial Engines

Radial77,

I think you posed a lot of questions that can only be answered with test equipment, machine shop time, and some flow analysis from an Engineer.

I'm not sure that he chose to keep the configuration. He had a bearing and then doubled up on them. What he tried was really cool but simple seems to always work better.
Old 08-03-2010, 08:55 AM
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Default RE: Everything Radial Engines

Hi All

Regarding smooth idle and transition off idle, there are other factors at play here. The Saito 325 has always had a centrifugal "blower" driven off the rear of the crank. It's unlikely to actually increase manifold pressure, but probably helps with fuel atomisation and more even distribution to the inlet manifolds and apparently more consistant fuel/air ratios. Nothing scientific here (!), but this should mean they are less likely to drop a cylinder at low speeds. A slightly rich mixture could put the glow "fire" out in a cylinder at low revs when there is a low airflow requirement.
I believe the mixing rotor/impeller must assist in this regard. I guess having dual glow plugs per cylinder also reduces the chances of a cylinder dying. Yes I know, we all run on-board glow drivers anyway.

I believe the major factor affecting smooth idle etc is valve timing. Have a listen to the engine in the attached video. The Saito reminds me of a cranky dragster engine (love it). I have the valve timing figures for maybe twenty 4 strokes including many of the radials. The cams run from ultra mild to quite wild (the Saito). I don't have the figures for the Moki, but I reckon they are likely to be on the wild side. A rump-rump idle, erratic off idle to mid range and a howling top end are often sure signs. With fairly crude carburettors, it is difficult to maintain accurate mixtures across the rev range with pumping inefficiencies due to big valve overlaps.

The OS Sirius 7 sounds smooth all the way, a bit like the OS 5 cyl which has fairly mild valve timing. A sharp bark from the exhaust usually indicates a healthy compression ratio, difficult to maintain accurately in these sizes where a few "thous" can mean a big difference. Of course, there is no real substitute for a big gasser radial !!

Regards RossG
radial1951

http://www.youtube.com/watch?v=ulL3j3vZzNA&amp;NR=1


ORIGINAL: Radial77

Hi cybertom,

your observation on the smoothness from idle to WOTon the SLseems accurate judging from the posts on youtube. i'm not really sure how this has been achieved (don't have the SL 150 yet) and I think its fair if SLEwant to keep this a design secret. But comparing it (SLEpics)to my MOKI150 it seems that the smoothness could be attributed by a more direct route the fuel takes to reach each cylinder??. Ithink OShas gone 1 step further with the sirius 7, and incorporated the rotor (turbulator?)post carb (not unlike the robart)and this makes the OSsound the smoothest from idle to WOT(again observation from videos). Thing is, the OSseems to sound"SO" smooth that it appears to have lost the radial beat!? Iknow you can't really compare a glowto agas burning radial... but the OSdoes seem too smooth. Will post here with test report pics and vid when i have the SLEin my hands.

R77.
Old 08-03-2010, 10:54 AM
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Default RE: Everything Radial Engines

Here is another radial engined CMP Zero that sounds pretty good.

[youtube]http://www.youtube.com/watch?v=zrN5o188rAs&playnext=1&videos=-elADqUflXM[/youtube]
Old 08-03-2010, 12:55 PM
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Default RE: Everything Radial Engines

The saito 325 fan is strictly for even fuel distribution. This engine's weakness is the poor carburetor which is very rich in the midrange thus wasting fuel...a lot of it. As I have posted earlier the OS 240/320 carb solves this well. Fuel consumption is way down along with much better running at all throttle settings. I do not use glow drivers on any of my multi cylinder engines. Some engines need it due to very uneven fuel distribution (saito 170 anyone?) I bought recently a saito 200 inline that as can be seen on any youtube video runs slobbery rich on the rear cylinder. I made a turbulator out of a nylon control horn cut to size and twirled with heat. I had to start the engine and reposition the turbulator many times until the engine runs evenly. Now it is a sweet runner. -Tom
Old 08-04-2010, 05:06 AM
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Default RE: Everything Radial Engines


[Quote] ORIGINALE : Cybertom

Radial77 ,

Penso che si pone un sacco di domande che non pu&ograve; che rispondere con le apparecchiature di prova , un negozio di macchina del tempo , e alcune analisi del flusso da un ingegnere.

Non sono sicuro che ha scelto di mantenere la configurazione. Aveva un cuscinetto e poi piegato in due su di essi. Che cosa ha provato &egrave; stato davvero cool , ma semplice sembra funzionare sempre meglio.

[/ quote]

<span class="long_text" id="result_box"><span title="" xc="For many factors radial engine Glow remain competitive in the categories of small engines up to 90cc." wc="Per molti fattori il motore radiale Glow rimarr&agrave; competitivo nella categorie di piccola cilindrata fino a 90cc massimo." closure_uid_en7po9="1547">For many factors radial engine Glow remain competitive in the categories of small engines up to 90cc.

</span><span title="" xc="So spin the turbine makes the aspiration in many ways more fluid operation I removed power." wc="Per cui la turbina centrifuga nell'aspirazione per molti versi rende pi&ugrave; fluido il funzionamento me ne toglie potenza." closure_uid_en7po9="1548" style="background-color: #fff">So spin the turbine makes the aspiration in many ways more fluid operation I removed power.

</span><span title="" xc="The dedicated suction without going through the crankcase, however, solves this problem because in my glow engines do not pass through the casing. " wc="L'aspirazione dedicata senza passare per il carter motore risolve per&ograve; questo problema infatti nei miei motori Glow non la faccio passare per il carter." closure_uid_en7po9="1549" style="background-color: #fff">The dedicated suction without going through the crankcase, however, solves this problem because in my glow engines do not pass through the casing. </span><span title="" xc="This gives me the advantage of always having clean mixture into the cylinders and an immediate recovery for munera rpm average." wc="Questo mi da il vantaggio di avere sempre miscela pulita nei cilindri ed una ripresa immediata per il munero di rpm medi." closure_uid_en7po9="1550">This gives me the advantage of always having clean mixture into the cylinders and an immediate recovery for munera rpm average.


</span><span title="" xc="Lasting glow engines but much less than gasoline because they oxidize more quickly and suffer from this if not cleaned very often." wc="I motori glow per&ograve; durano molto meno di quelli a benzina perch&egrave; si ossidano molto pi&ugrave; velocemente e risentono di questo se non puliti con molta frequenza." closure_uid_en7po9="1551">Lasting glow engines but much less than gasoline because they oxidize more quickly and suffer from this if not cleaned very often.

</span><span title="" xc="Then the same consumption gasoline engines are much more precise radial and much more powerful than their weight. " wc="Poi a parit&agrave; di consumi i motori a benzina radiali sono molto pi&ugrave; precisi e molto pi&ugrave; potenti rispetto al loro peso." closure_uid_en7po9="1552">Then the same consumption gasoline engines are much more precise radial and much more powerful than their weight. </span><span title="" xc="And especially not because they oxidize the fuel and lubricant already." wc="E sopratutto non si ossidano perch&egrave; la benzina e gi&agrave; lubrificante." closure_uid_en7po9="1553">And especially not because they oxidize the fuel and lubricant already.

</span><span title="" xc="In my opinion some Japanese engines like Saito and OS and others, wanted to improve the rpm range to make it smoother but took the realism of the sound of true radial engines because their sound is very similar to that of the true radial engines." wc="Secondo il mio parere alcuni motori giapponesi tipo Saito e OS ed altri, hanno voluto migliorare la gamma di giri per renderla pi&ugrave; fluida ma hanno preso nel realismo del suono dei veri motori radiali infatti il loro suono non assomiglia molto a quello dei veri motori radiali." closure_uid_en7po9="1554" style="color: #000; background-color: #e6ecf9">In my opinion some Japanese engines like Saito and OS and others, wanted to improve the rpm range to make it smoother but took the realism of the sound of true radial engines because their sound is very similar to that of the true radial engines.</span></span>
Old 08-04-2010, 05:09 AM
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Old 08-04-2010, 10:12 AM
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Default RE: Everything Radial Engines

I wish I had the talent, and the machines, to produce such lovely art in metal! [sm=thumbup.gif]
Old 08-04-2010, 08:57 PM
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Agreed..... SHOOT!! i wish i had the money to buy such art..ugg
Old 08-04-2010, 10:27 PM
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Default RE: Everything Radial Engines

Radial1951,

We were speaking specifically of GAS radial engines. Glow powered radial engines don't apply to this comparison because there are too many significant differences: fuel, lubricant, carburetion, ignition system, compression...
Old 08-05-2010, 02:55 AM
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Default RE: Everything Radial Engines

ORIGINAL: Cybertom

Radial77,

I think you posed a lot of questions that can only be answered with test equipment, machine shop time, and some flow analysis from an Engineer.

I'm not sure that he chose to keep the configuration. He had a bearing and then doubled up on them. What he tried was really cool but simple seems to always work better.
Cybertom,

Yup - agree wholeheartedly on the flow analysis, but having said that, real life results would probably enable closer modelling (computing) accuracy. As fancy as flow modelling, CFD and FEAare ; the GIGOprinciple still applies. But yup, you're right that those variables would need computing power to visualise.


SLEngines,

The photos of the engine(s)you posted above are beautiful! You're probably an alienwho happensto live in Italy...........
Old 08-06-2010, 02:34 PM
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Default RE: Everything Radial Engines

Cybertom

Sorry, but "we" were NOT speaking specifically of gas engines. My post was in reply to Radial77 who specifically mentioned the OS Sirius, Robart and Heilemann radials, all glow engines, and their use of a centrifugal pump, however crude, to assist fuel distribution and therefore smooth operation. Even S.L.engines referred to his own glow engines and the use of a "turbine" as well as referring to Saito and OS design features.

Unfortunately, in this instance, smooth usually equates to some loss of that magic radial sound, the very thing we want to keep.

Regards, radial1951


ORIGINAL: Cybertom

Radial1951,

We were speaking specifically of GAS radial engines. Glow powered radial engines don't apply to this comparison because there are too many significant differences: fuel, lubricant, carburetion, ignition system, compression...
Old 08-06-2010, 09:36 PM
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Default RE: Everything Radial Engines

Radial1951,

My Robart R780 has excellent sound when it's at idle or wide open. It's transision is verty smooth creating a wide usable range of throttle. Nothing lost here.

What I am getting at is the SL 150 seems to exhibit a lot of the same charateristics as my R780. I want to see a really good video clip of the SL 150 in action on a flying aircraft. If the aircraft does a slow flyby a reduced throttle and the engine sounds like radial music at a variety of speeds I will be sold. A test bench is one thing...flying is another.

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Old 08-07-2010, 02:42 AM
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Default RE: Everything Radial Engines

You are absolutely right. Until we see this engine in a plane or hear someone actually puchasing one I'm still a bit sceptical about it. I have sent him an email asking some pretty basic questions but never got any reply.
Old 08-07-2010, 03:10 AM
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Cybertom,

Do the glow engines have the same beat as gas? The robart seem pretty smooth. Sounds very much like the FR420 (all these on video). haven't heard the 420 "live" yet but have seen one in the flesh - and DAMN! it's one beautiful piece of engineering! yet to see one flying in a plane!

fredo,

did you get SLE's e-mail correct. He's usually very prompt with e-mails. I placed an order for the 150 after a long "chat" via e-mail. Fingers crossed should be getting it sometime in September. Ijust hope itruns as good as it looks..................

R77.
Old 08-07-2010, 03:26 AM
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ORIGINAL: fredo

You are absolutely right. Until we see this engine in a plane or hear someone actually puchasing one I'm still a bit sceptical about it. I have sent him an email asking some pretty basic questions but never got any reply.


I have not received any mail that has never responded I think it ended in spam.Resend this email address please:


[email protected]
Old 08-18-2010, 04:00 PM
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Hi,
Just to let you radial engine fans know I purchased a SL 90 from Luigi Spalla for my collection of engines, he had two for sale, and made me a really good offer for one.
About a week and a half later a beautifully made wooden box with the logo lazer cut into it arrived at the door. This engine is beautifully made, very nice machining.
Just to look at the heads imagening the machining operationes are fasinating, and beautiful looks, similar to my Robart radial, with everything enclosed, rockers, pushrods, oilsump with glass, tubes between rocker housings, welded motor mount, just like the real thing.
Reminds me about the Aussie Rotec radials for exprimental aircraft.
Luigi says he is not making the engine aneymore, but puts his effort into the SL 150 gas engine, beautiful sounding idle in his video.
I do plan to start the SL 90 when I get going making a stand for it, planning a welded stand, wit changeable firewalls for each engine I want to run.
They really have some exelent machinists in Italy within model building, not just the Ferrari..................
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Old 08-18-2010, 04:29 PM
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Very nice!!
Old 08-24-2010, 09:06 AM
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Hey everybody. This thread is too quiet! Does anybody own or know much about the Seidel ST7-35? Looks like it could be a cute nice little engine. I wonder if Hobby King will stock them. -Tom
Old 08-24-2010, 09:30 AM
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I emailed UMS about this one.... "I am interested in buying your Seidel UMS Radial Engine ST 7 - 35. Do you have them available for sale right now? However, your price of 1,417.50 USD is only $31.50 USD less than I paid for my Seidel UMS ST-9-90 from HobbyKing.com. I understand that Hobby king does not yet carry the ST-7-35 model, but do you know if you will be supplying this engine to them soon? If not, will you consider adjusting your price for the ST-7-35?"

Their reply was "Greetings and good day. Thanks for your interest on our Radial engines. We wish to inform you that our Radial engine ST 7-35 CC is under development and expected to be available by the end of August 2010. Please let us know your complete shipping address with contact number, in order to send our proforma invoice."

I just sent them my contact info today, so am expecting a quote soon, but no word on HK getting a supply.
Old 08-24-2010, 02:39 PM
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HI,
I just got an e-mail from UMS telling me the first batch of the 7-35 will be ready for delivery in mid september. I had ordered one from UMS, but uopn finding out they where not ready, I managed to buy a early pre production engine from a dealer in the UK. (weston UK .recomended).
I have posted comments and pictures about this engine earlier on this tread ( about may) comparing the bigger 7 and the small 7-35.
I have been to busy this summer to start it, but really think this engine wil be popular due to the smaller size, and a lot more models that will be suitable for the engine.
It is really a neat sice radial engine, almost as small as the Thecnopower radials.
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Old 08-24-2010, 02:45 PM
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Very nice find and nice photos! In the cowl, it can really resemble a Bentley BR2 (but of course, it won't spin). Would be great for WWI bird.
Old 08-24-2010, 03:45 PM
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Thank you to both of you describing or looking into this smaller radial. I did send a message to Hobby King inquiring about carrying it. I have not heard back yet. Looks great!!! I hope I can snag one if they get a few. -Tom

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