No baffles needed. QQ flies in the same club as me here in Florida. IT's hot here.. way hotter than Germany.. we have no issues. I flew mine all summer. No issues. Just tune it properly and forget it.

Originally Posted by The Count

Hi...

Now the Falcon spinner 4,5" is here.
I want to know values about max. temperatures for the DA70. How much should the temps be?
Its important to avoid overheating, all guys here in Germany recommend baffles for DA70... therefore I want to measure first.
Thanks

If no baffles works for you, great, less work to get in the air.
For me properly baffling & venting the cowl opening/sides & fuselage to optimise air in and out is essential to a successful maiden.
Personal experience suggests good baffling especially with a big round cowl, helps with keeping an engine running cool.
I've also found tuning to be more consistent due to better airflow within the cowl.
I'll add some pics to explain what I'm trying to say...........................
Cheers,
Pete

Thanks, Cdi, I know QQ says no needed and yes, its hotter in Florida. Two facts!

Peter, your Baffles looks good, nice work. I got a solution from a guy he also made Baffles.More cooling is always better.

William, yes, opening the cowl a bit around is good, I should do the same.

.... BUT... How much are the temps with/without Baffles on the Mamba ??? Values needed.

I talked with Da they recommended a pie plate type baffle open in front of the cylinders

It is what I did here in California. Tuned it when temps were at 100 and now they are in their 50s

Runs perect great transition idle and top end

I have not touched them needle since the initial tune

Exit air is more important than inlet air

Tune exactly pr tunning instructions in flying giants

I think if it is good enough for QQ it is good enough

Dennis

What do you mean with pie plate type baffle?
Are there pics?

Guessing he means just cover the half circle above and below where the cylinders sit. I have a picture of my Sopwith with temporary cardboard in place in this style.

(Working on the scale bits to replace the cardboard now.)

As Dennis22 said, the most important thing is that you have more exit area than inlet area. On the Mamba, that big, fat 5" spinner accomplishes this by restricting the inlet area. It's not directed, but the airflow should be good.

Originally Posted by The Count

What do you mean with pie plate type baffle?
Are there pics?

Just a simple plate in the front that blocks above and below the cylinders exactly as Nergell did on the Sopwith.


Open up the back of the scoop on the bottom of the cowl and don't block the air going through the pipe tunnel.


Getting a good tune is critical.


Dennis

It is my belief that almost any engine would benefit from good baffling for cooling. Based on the shape of the Mamba's cowl, I am building a wind funnel with circular inlet using foam sheet to capture all air coming into the cowl inlet instead of baffles that could block some of the inlet areas. This is to maximize the air intake area.

I gradually constricted the funnel outlet area and shaped it around the engine to guide the air across the engine fins and toward the desired location. This creates a Venturi effect and results high velocity air flows through a constricted section around the fins.

I cut several air exit openings on the cowl. This is to ensure I have the total exit areas about 3 times the total constricted section across the engine fins. The exit openings are covered with vent fins to help reduce the air pressure at the exits. This should result higher differential pressure between the cowl air intake and the exits, and allow maximum air flow across the engine fins.

TVo

Hi...

Yesterday I talked with the distributor of the DA70 engines here in Germany.
He said cooling is important but you need a good airflow around the engine. Cooling to the front and nothing in the back would not the solution. Design for baffling is also a point.... long words, thinking lot.... I wil open the front, increase the diameter and that will fit with my louvers in the cowl.

Originally Posted by The Count

Hi...

Yesterday I talked with the distributor of the DA70 engines here in Germany.
He said cooling is important but you need a good airflow around the engine. Cooling to the front and nothing in the back would not the solution. Design for baffling is also a point.... long words, thinking lot.... I wil open the front, increase the diameter and that will fit with my louvers in the cowl.

Good work on your front baffle plates, perfect fit to the cylinder fins. I assume you are yet to duct air to the rear of the cylinders then out via louvres in the cowl & fuselage bottom?
I saw 70 deg. C. temperature drop with my baffles, ducting and venting arrangement.
I try to keep internal ducting simple and removable, held in place by the cowl.
Some pictures always help my long winded descriptions.

Originally Posted by William_Burkert

I opened up the front of the cowl 1/4” all the way around, nice surprise result is how well centered the engine appears. The cowl opening needed a little cleaning up so why not a little more?

I also opened the front. Marked the max possible diameter with two taped pencils, one is deeper so I caught follow the inner diameter. Easy solution.
Taped the line with clear tape and grinded with a tool named DREMEL.
Fitted with sandpaper.... and wow, that modification is recommended, have to make a pic to see the difference.
Thanks, William!

Useless effort and added weight. This motor has plenty of cooling, nothing needed extra, as we fly in 100 degree temps here and have no issues.

Cdi, I have found that that in the baffling/no baffling discussions, the guys who state that their planes are unbaffled and fly fine tend to be ignored. There are two very big names being tossed around in this thread - DA and QQ - and it's just my gut that if baffling really was important, it would be addressed in the manual. It didn't matter to some that Jase D stated that he flew his EF MXS with no baffling - there were still those that insisted you had to have it. There were three at our field with DA 120s, including mine, that were unbaffled, and all flew fine. Oh well....

Originally Posted by FGNewbie

Cdi, I have found that that in the baffling/no baffling discussions, the guys who state that their planes are unbaffled and fly fine tend to be ignored. There are two very big names being tossed around in this thread - DA and QQ - and it's just my gut that if baffling really was important, it would be addressed in the manual. It didn't matter to some that Jase D stated that he flew his EF MXS with no baffling - there were still those that insisted you had to have it. There were three at our field with DA 120s, including mine, that were unbaffled, and all flew fine. Oh well....

+1


Additionally enlarging the opening may be counter productive if outlet aerie is not proportionally increased.


The Good news is that it is unlikely to hurt your engine if you do add baffles


By the way I run the recommended 5" spinner, fly in 100* temps in the summer with no problem


I would listen to DA and QQ


What ever you do you are in for a real treat when you get it in the air


Dennis